Query and filter data

Firestore provides powerful query functionality for specifying which documents you want to retrieve from a collection or collection group. These queries can also be used with either get() or addSnapshotListener(), as described in Get Data and Get Realtime Updates.

Example data

To get started, write some data about cities so we can look at different ways to read it back:

Web version 9

import { collection, doc, setDoc } from "firebase/firestore"; 

const citiesRef = collection(db, "cities");

await setDoc(doc(citiesRef, "SF"), {
    name: "San Francisco", state: "CA", country: "USA",
    capital: false, population: 860000,
    regions: ["west_coast", "norcal"] });
await setDoc(doc(citiesRef, "LA"), {
    name: "Los Angeles", state: "CA", country: "USA",
    capital: false, population: 3900000,
    regions: ["west_coast", "socal"] });
await setDoc(doc(citiesRef, "DC"), {
    name: "Washington, D.C.", state: null, country: "USA",
    capital: true, population: 680000,
    regions: ["east_coast"] });
await setDoc(doc(citiesRef, "TOK"), {
    name: "Tokyo", state: null, country: "Japan",
    capital: true, population: 9000000,
    regions: ["kanto", "honshu"] });
await setDoc(doc(citiesRef, "BJ"), {
    name: "Beijing", state: null, country: "China",
    capital: true, population: 21500000,
    regions: ["jingjinji", "hebei"] });

Web version 8

var citiesRef = db.collection("cities");

citiesRef.doc("SF").set({
    name: "San Francisco", state: "CA", country: "USA",
    capital: false, population: 860000,
    regions: ["west_coast", "norcal"] });
citiesRef.doc("LA").set({
    name: "Los Angeles", state: "CA", country: "USA",
    capital: false, population: 3900000,
    regions: ["west_coast", "socal"] });
citiesRef.doc("DC").set({
    name: "Washington, D.C.", state: null, country: "USA",
    capital: true, population: 680000,
    regions: ["east_coast"] });
citiesRef.doc("TOK").set({
    name: "Tokyo", state: null, country: "Japan",
    capital: true, population: 9000000,
    regions: ["kanto", "honshu"] });
citiesRef.doc("BJ").set({
    name: "Beijing", state: null, country: "China",
    capital: true, population: 21500000,
    regions: ["jingjinji", "hebei"] });
Swift
Note: This product is not available on watchOS and App Clip targets.
let citiesRef = db.collection("cities")

citiesRef.document("SF").setData([
  "name": "San Francisco",
  "state": "CA",
  "country": "USA",
  "capital": false,
  "population": 860000,
  "regions": ["west_coast", "norcal"]
])
citiesRef.document("LA").setData([
  "name": "Los Angeles",
  "state": "CA",
  "country": "USA",
  "capital": false,
  "population": 3900000,
  "regions": ["west_coast", "socal"]
])
citiesRef.document("DC").setData([
  "name": "Washington D.C.",
  "country": "USA",
  "capital": true,
  "population": 680000,
  "regions": ["east_coast"]
])
citiesRef.document("TOK").setData([
  "name": "Tokyo",
  "country": "Japan",
  "capital": true,
  "population": 9000000,
  "regions": ["kanto", "honshu"]
])
citiesRef.document("BJ").setData([
  "name": "Beijing",
  "country": "China",
  "capital": true,
  "population": 21500000,
  "regions": ["jingjinji", "hebei"]
])
Objective-C
Note: This product is not available on watchOS and App Clip targets.
FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];
[[citiesRef documentWithPath:@"SF"] setData:@{
  @"name": @"San Francisco",
  @"state": @"CA",
  @"country": @"USA",
  @"capital": @(NO),
  @"population": @860000,
  @"regions": @[@"west_coast", @"norcal"]
}];
[[citiesRef documentWithPath:@"LA"] setData:@{
  @"name": @"Los Angeles",
  @"state": @"CA",
  @"country": @"USA",
  @"capital": @(NO),
  @"population": @3900000,
  @"regions": @[@"west_coast", @"socal"]
}];
[[citiesRef documentWithPath:@"DC"] setData:@{
  @"name": @"Washington D.C.",
  @"country": @"USA",
  @"capital": @(YES),
  @"population": @680000,
  @"regions": @[@"east_coast"]
}];
[[citiesRef documentWithPath:@"TOK"] setData:@{
  @"name": @"Tokyo",
  @"country": @"Japan",
  @"capital": @(YES),
  @"population": @9000000,
  @"regions": @[@"kanto", @"honshu"]
}];
[[citiesRef documentWithPath:@"BJ"] setData:@{
  @"name": @"Beijing",
  @"country": @"China",
  @"capital": @(YES),
  @"population": @21500000,
  @"regions": @[@"jingjinji", @"hebei"]
}];
Kotlin
Android
val cities = db.collection("cities")

val data1 = hashMapOf(
    "name" to "San Francisco",
    "state" to "CA",
    "country" to "USA",
    "capital" to false,
    "population" to 860000,
    "regions" to listOf("west_coast", "norcal"),
)
cities.document("SF").set(data1)

val data2 = hashMapOf(
    "name" to "Los Angeles",
    "state" to "CA",
    "country" to "USA",
    "capital" to false,
    "population" to 3900000,
    "regions" to listOf("west_coast", "socal"),
)
cities.document("LA").set(data2)

val data3 = hashMapOf(
    "name" to "Washington D.C.",
    "state" to null,
    "country" to "USA",
    "capital" to true,
    "population" to 680000,
    "regions" to listOf("east_coast"),
)
cities.document("DC").set(data3)

val data4 = hashMapOf(
    "name" to "Tokyo",
    "state" to null,
    "country" to "Japan",
    "capital" to true,
    "population" to 9000000,
    "regions" to listOf("kanto", "honshu"),
)
cities.document("TOK").set(data4)

val data5 = hashMapOf(
    "name" to "Beijing",
    "state" to null,
    "country" to "China",
    "capital" to true,
    "population" to 21500000,
    "regions" to listOf("jingjinji", "hebei"),
)
cities.document("BJ").set(data5)
Java
Android
CollectionReference cities = db.collection("cities");

Map<String, Object> data1 = new HashMap<>();
data1.put("name", "San Francisco");
data1.put("state", "CA");
data1.put("country", "USA");
data1.put("capital", false);
data1.put("population", 860000);
data1.put("regions", Arrays.asList("west_coast", "norcal"));
cities.document("SF").set(data1);

Map<String, Object> data2 = new HashMap<>();
data2.put("name", "Los Angeles");
data2.put("state", "CA");
data2.put("country", "USA");
data2.put("capital", false);
data2.put("population", 3900000);
data2.put("regions", Arrays.asList("west_coast", "socal"));
cities.document("LA").set(data2);

Map<String, Object> data3 = new HashMap<>();
data3.put("name", "Washington D.C.");
data3.put("state", null);
data3.put("country", "USA");
data3.put("capital", true);
data3.put("population", 680000);
data3.put("regions", Arrays.asList("east_coast"));
cities.document("DC").set(data3);

Map<String, Object> data4 = new HashMap<>();
data4.put("name", "Tokyo");
data4.put("state", null);
data4.put("country", "Japan");
data4.put("capital", true);
data4.put("population", 9000000);
data4.put("regions", Arrays.asList("kanto", "honshu"));
cities.document("TOK").set(data4);

Map<String, Object> data5 = new HashMap<>();
data5.put("name", "Beijing");
data5.put("state", null);
data5.put("country", "China");
data5.put("capital", true);
data5.put("population", 21500000);
data5.put("regions", Arrays.asList("jingjinji", "hebei"));
cities.document("BJ").set(data5);

Dart

final cities = db.collection("cities");
final data1 = <String, dynamic>{
  "name": "San Francisco",
  "state": "CA",
  "country": "USA",
  "capital": false,
  "population": 860000,
  "regions": ["west_coast", "norcal"]
};
cities.doc("SF").set(data1);

final data2 = <String, dynamic>{
  "name": "Los Angeles",
  "state": "CA",
  "country": "USA",
  "capital": false,
  "population": 3900000,
  "regions": ["west_coast", "socal"],
};
cities.doc("LA").set(data2);

final data3 = <String, dynamic>{
  "name": "Washington D.C.",
  "state": null,
  "country": "USA",
  "capital": true,
  "population": 680000,
  "regions": ["east_coast"]
};
cities.doc("DC").set(data3);

final data4 = <String, dynamic>{
  "name": "Tokyo",
  "state": null,
  "country": "Japan",
  "capital": true,
  "population": 9000000,
  "regions": ["kanto", "honshu"]
};
cities.doc("TOK").set(data4);

final data5 = <String, dynamic>{
  "name": "Beijing",
  "state": null,
  "country": "China",
  "capital": true,
  "population": 21500000,
  "regions": ["jingjinji", "hebei"],
};
cities.doc("BJ").set(data5);
Java
CollectionReference cities = db.collection("cities");
List<ApiFuture<WriteResult>> futures = new ArrayList<>();
futures.add(
    cities
        .document("SF")
        .set(
            new City(
                "San Francisco",
                "CA",
                "USA",
                false,
                860000L,
                Arrays.asList("west_coast", "norcal"))));
futures.add(
    cities
        .document("LA")
        .set(
            new City(
                "Los Angeles",
                "CA",
                "USA",
                false,
                3900000L,
                Arrays.asList("west_coast", "socal"))));
futures.add(
    cities
        .document("DC")
        .set(
            new City(
                "Washington D.C.", null, "USA", true, 680000L, Arrays.asList("east_coast"))));
futures.add(
    cities
        .document("TOK")
        .set(
            new City(
                "Tokyo", null, "Japan", true, 9000000L, Arrays.asList("kanto", "honshu"))));
futures.add(
    cities
        .document("BJ")
        .set(
            new City(
                "Beijing",
                null,
                "China",
                true,
                21500000L,
                Arrays.asList("jingjinji", "hebei"))));
// (optional) block on documents successfully added
ApiFutures.allAsList(futures).get();
Python
class City:
    def __init__(self, name, state, country, capital=False, population=0, regions=[]):
        self.name = name
        self.state = state
        self.country = country
        self.capital = capital
        self.population = population
        self.regions = regions

    @staticmethod
    def from_dict(source):
        # ...

    def to_dict(self):
        # ...

    def __repr__(self):
        return f"City(\
                name={self.name}, \
                country={self.country}, \
                population={self.population}, \
                capital={self.capital}, \
                regions={self.regions}\
            )"
cities_ref = db.collection("cities")
cities_ref.document("BJ").set(
    City("Beijing", None, "China", True, 21500000, ["hebei"]).to_dict()
)
cities_ref.document("SF").set(
    City(
        "San Francisco", "CA", "USA", False, 860000, ["west_coast", "norcal"]
    ).to_dict()
)
cities_ref.document("LA").set(
    City(
        "Los Angeles", "CA", "USA", False, 3900000, ["west_coast", "socal"]
    ).to_dict()
)
cities_ref.document("DC").set(
    City("Washington D.C.", None, "USA", True, 680000, ["east_coast"]).to_dict()
)
cities_ref.document("TOK").set(
    City("Tokyo", None, "Japan", True, 9000000, ["kanto", "honshu"]).to_dict()
)
Python
(Async)
class City:
    def __init__(self, name, state, country, capital=False, population=0, regions=[]):
        self.name = name
        self.state = state
        self.country = country
        self.capital = capital
        self.population = population
        self.regions = regions

    @staticmethod
    def from_dict(source):
        # ...

    def to_dict(self):
        # ...

    def __repr__(self):
        return f"City(\
                name={self.name}, \
                country={self.country}, \
                population={self.population}, \
                capital={self.capital}, \
                regions={self.regions}\
            )"
cities_ref = db.collection("cities")
await cities_ref.document("BJ").set(
    City("Beijing", None, "China", True, 21500000, ["hebei"]).to_dict()
)
await cities_ref.document("SF").set(
    City(
        "San Francisco", "CA", "USA", False, 860000, ["west_coast", "norcal"]
    ).to_dict()
)
await cities_ref.document("LA").set(
    City(
        "Los Angeles", "CA", "USA", False, 3900000, ["west_coast", "socal"]
    ).to_dict()
)
await cities_ref.document("DC").set(
    City("Washington D.C.", None, "USA", True, 680000, ["east_coast"]).to_dict()
)
await cities_ref.document("TOK").set(
    City("Tokyo", None, "Japan", True, 9000000, ["kanto", "honshu"]).to_dict()
)
C++
CollectionReference cities = db->Collection("cities");

cities.Document("SF").Set({
    {"name", FieldValue::String("San Francisco")},
    {"state", FieldValue::String("CA")},
    {"country", FieldValue::String("USA")},
    {"capital", FieldValue::Boolean(false)},
    {"population", FieldValue::Integer(860000)},
    {"regions", FieldValue::Array({FieldValue::String("west_coast"),
                                   FieldValue::String("norcal")})},
});

cities.Document("LA").Set({
    {"name", FieldValue::String("Los Angeles")},
    {"state", FieldValue::String("CA")},
    {"country", FieldValue::String("USA")},
    {"capital", FieldValue::Boolean(false)},
    {"population", FieldValue::Integer(3900000)},
    {"regions", FieldValue::Array({FieldValue::String("west_coast"),
                                   FieldValue::String("socal")})},
});

cities.Document("DC").Set({
    {"name", FieldValue::String("Washington D.C.")},
    {"state", FieldValue::Null()},
    {"country", FieldValue::String("USA")},
    {"capital", FieldValue::Boolean(true)},
    {"population", FieldValue::Integer(680000)},
    {"regions",
     FieldValue::Array({FieldValue::String("east_coast")})},
});

cities.Document("TOK").Set({
    {"name", FieldValue::String("Tokyo")},
    {"state", FieldValue::Null()},
    {"country", FieldValue::String("Japan")},
    {"capital", FieldValue::Boolean(true)},
    {"population", FieldValue::Integer(9000000)},
    {"regions", FieldValue::Array({FieldValue::String("kanto"),
                                   FieldValue::String("honshu")})},
});

cities.Document("BJ").Set({
    {"name", FieldValue::String("Beijing")},
    {"state", FieldValue::Null()},
    {"country", FieldValue::String("China")},
    {"capital", FieldValue::Boolean(true)},
    {"population", FieldValue::Integer(21500000)},
    {"regions", FieldValue::Array({FieldValue::String("jingjinji"),
                                   FieldValue::String("hebei")})},
});
Node.js
const citiesRef = db.collection('cities');

await citiesRef.doc('SF').set({
  name: 'San Francisco', state: 'CA', country: 'USA',
  capital: false, population: 860000,
  regions: ['west_coast', 'norcal']
});
await citiesRef.doc('LA').set({
  name: 'Los Angeles', state: 'CA', country: 'USA',
  capital: false, population: 3900000,
  regions: ['west_coast', 'socal']
});
await citiesRef.doc('DC').set({
  name: 'Washington, D.C.', state: null, country: 'USA',
  capital: true, population: 680000,
  regions: ['east_coast']
});
await citiesRef.doc('TOK').set({
  name: 'Tokyo', state: null, country: 'Japan',
  capital: true, population: 9000000,
  regions: ['kanto', 'honshu']
});
await citiesRef.doc('BJ').set({
  name: 'Beijing', state: null, country: 'China',
  capital: true, population: 21500000,
  regions: ['jingjinji', 'hebei']
});
Go
cities := []struct {
	id string
	c  City
}{
	{
		id: "SF",
		c: City{Name: "San Francisco", State: "CA", Country: "USA",
			Capital: false, Population: 860000,
			Regions: []string{"west_coast", "norcal"}},
	},
	{
		id: "LA",
		c: City{Name: "Los Angeles", State: "CA", Country: "USA",
			Capital: false, Population: 3900000,
			Regions: []string{"west_coast", "socal"}},
	},
	{
		id: "DC",
		c: City{Name: "Washington D.C.", Country: "USA",
			Capital: true, Population: 680000,
			Regions: []string{"east_coast"}},
	},
	{
		id: "TOK",
		c: City{Name: "Tokyo", Country: "Japan",
			Capital: true, Population: 9000000,
			Regions: []string{"kanto", "honshu"}},
	},
	{
		id: "BJ",
		c: City{Name: "Beijing", Country: "China",
			Capital: true, Population: 21500000,
			Regions: []string{"jingjinji", "hebei"}},
	},
}
for _, c := range cities {
	if _, err := client.Collection("cities").Doc(c.id).Set(ctx, c.c); err != nil {
		return err
	}
}
PHP
$citiesRef = $db->collection('samples/php/cities');
$citiesRef->document('SF')->set([
    'name' => 'San Francisco',
    'state' => 'CA',
    'country' => 'USA',
    'capital' => false,
    'population' => 860000,
    'density' => 18000,
    'regions' => ['west_coast', 'norcal']
]);
$citiesRef->document('LA')->set([
    'name' => 'Los Angeles',
    'state' => 'CA',
    'country' => 'USA',
    'capital' => false,
    'population' => 3900000,
    'density' => 8000,
    'regions' => ['west_coast', 'socal']
]);
$citiesRef->document('DC')->set([
    'name' => 'Washington D.C.',
    'state' => null,
    'country' => 'USA',
    'capital' => true,
    'population' => 680000,
    'density' => 11000,
    'regions' => ['east_coast']
]);
$citiesRef->document('TOK')->set([
    'name' => 'Tokyo',
    'state' => null,
    'country' => 'Japan',
    'capital' => true,
    'population' => 9000000,
    'density' => 16000,
    'regions' => ['kanto', 'honshu']
]);
$citiesRef->document('BJ')->set([
    'name' => 'Beijing',
    'state' => null,
    'country' => 'China',
    'capital' => true,
    'population' => 21500000,
    'density' => 3500,
    'regions' => ['jingjinji', 'hebei']
]);
printf('Added example cities data to the cities collection.' . PHP_EOL);
Unity
CollectionReference citiesRef = db.Collection("cities");
citiesRef.Document("SF").SetAsync(new Dictionary<string, object>(){
    { "Name", "San Francisco" },
    { "State", "CA" },
    { "Country", "USA" },
    { "Capital", false },
    { "Population", 860000 },
    { "Regions", new ArrayList{"west_coast", "norcal"} }
});
citiesRef.Document("LA").SetAsync(new Dictionary<string, object>(){
    { "Name", "Los Angeles" },
    { "State", "CA" },
    { "Country", "USA" },
    { "Capital", false },
    { "Population", 3900000 },
    { "Regions", new ArrayList{"west_coast", "socal"} }
});
citiesRef.Document("DC").SetAsync(new Dictionary<string, object>(){
    { "Name", "Washington D.C." },
    { "State", null },
    { "Country", "USA" },
    { "Capital", true },
    { "Population", 680000 },
    { "Regions", new ArrayList{"east_coast"} }
});
citiesRef.Document("TOK").SetAsync(new Dictionary<string, object>(){
    { "Name", "Tokyo" },
    { "State", null },
    { "Country", "Japan" },
    { "Capital", true },
    { "Population", 9000000 },
    { "Regions", new ArrayList{"kanto", "honshu"} }
});
citiesRef.Document("BJ").SetAsync(new Dictionary<string, object>(){
    { "Name", "Beijing" },
    { "State", null },
    { "Country", "China" },
    { "Capital", true },
    { "Population", 21500000 },
    { "Regions", new ArrayList{"jingjinji", "hebei"} }
});
C#
CollectionReference citiesRef = db.Collection("cities");
await citiesRef.Document("SF").SetAsync(new Dictionary<string, object>
{
    { "Name", "San Francisco" },
    { "State", "CA" },
    { "Country", "USA" },
    { "Capital", false },
    { "Population", 860000 },
    { "Density", 18000 },
    { "Regions", new[] {"west_coast", "norcal"} }
});
await citiesRef.Document("LA").SetAsync(new Dictionary<string, object>
{
    { "Name", "Los Angeles" },
    { "State", "CA" },
    { "Country", "USA" },
    { "Capital", false },
    { "Population", 3900000 },
    { "Density", 8300 },
    { "Regions", new[] {"west_coast", "socal"} }
});
await citiesRef.Document("DC").SetAsync(new Dictionary<string, object>
{
    { "Name", "Washington D.C." },
    { "State", null },
    { "Country", "USA" },
    { "Capital", true },
    { "Population", 680000 },
    { "Density", 11300 },
    { "Regions", new[] {"east_coast"} }
});
await citiesRef.Document("TOK").SetAsync(new Dictionary<string, object>
{
    { "Name", "Tokyo" },
    { "State", null },
    { "Country", "Japan" },
    { "Capital", true },
    { "Population", 9000000 },
    { "Density", 16000 },
    { "Regions", new[] {"kanto", "honshu"} }
});
await citiesRef.Document("BJ").SetAsync(new Dictionary<string, object>
{
    { "Name", "Beijing" },
    { "State", null },
    { "Country", "China" },
    { "Capital", true },
    { "Population", 21500000 },
    { "Density", 3500 },
    { "Regions", new[] {"jingjinji", "hebei"} }
});
Console.WriteLine("Added example cities data to the cities collection.");
Ruby
cities_ref = firestore.col collection_path
cities_ref.doc("SF").set(
  {
    name:       "San Francisco",
    state:      "CA",
    country:    "USA",
    capital:    false,
    population: 860_000,
    regions:    ["west_coast", "norcal"]
  }
)
cities_ref.doc("LA").set(
  {
    name:       "Los Angeles",
    state:      "CA",
    country:    "USA",
    capital:    false,
    population: 3_900_000,
    regions:    ["west_coast", "socal"]
  }
)
cities_ref.doc("DC").set(
  {
    name:       "Washington D.C.",
    state:      nil,
    country:    "USA",
    capital:    true,
    population: 680_000,
    regions:    ["east_coast"]
  }
)
cities_ref.doc("TOK").set(
  {
    name:       "Tokyo",
    state:      nil,
    country:    "Japan",
    capital:    true,
    population: 9_000_000,
    regions:    ["kanto", "honshu"]
  }
)
cities_ref.doc("BJ").set(
  {
    name:       "Beijing",
    state:      nil,
    country:    "China",
    capital:    true,
    population: 21_500_000,
    regions:    ["jingjinji", "hebei"]
  }
)

Simple queries

The following query returns all cities with state CA:

Web version 9

// Create a reference to the cities collection
import { collection, query, where } from "firebase/firestore";
const citiesRef = collection(db, "cities");

// Create a query against the collection.
const q = query(citiesRef, where("state", "==", "CA"));

Web version 8

// Create a reference to the cities collection
var citiesRef = db.collection("cities");

// Create a query against the collection.
var query = citiesRef.where("state", "==", "CA");
Swift
Note: This product is not available on watchOS and App Clip targets.
// Create a reference to the cities collection
let citiesRef = db.collection("cities")

// Create a query against the collection.
let query = citiesRef.whereField("state", isEqualTo: "CA")
Objective-C
Note: This product is not available on watchOS and App Clip targets.
// Create a reference to the cities collection
FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];
// Create a query against the collection.
FIRQuery *query = [citiesRef queryWhereField:@"state" isEqualTo:@"CA"];
Kotlin
Android
// Create a reference to the cities collection
val citiesRef = db.collection("cities")

// Create a query against the collection.
val query = citiesRef.whereEqualTo("state", "CA")
Java
Android
// Create a reference to the cities collection
CollectionReference citiesRef = db.collection("cities");

// Create a query against the collection.
Query query = citiesRef.whereEqualTo("state", "CA");

Dart

// Create a reference to the cities collection
final citiesRef = db.collection("cities");

// Create a query against the collection.
final query = citiesRef.where("state", isEqualTo: "CA");
Java
// Create a reference to the cities collection
CollectionReference cities = db.collection("cities");
// Create a query against the collection.
Query query = cities.whereEqualTo("state", "CA");
// retrieve  query results asynchronously using query.get()
ApiFuture<QuerySnapshot> querySnapshot = query.get();

for (DocumentSnapshot document : querySnapshot.get().getDocuments()) {
  System.out.println(document.getId());
}
Python
# Create a reference to the cities collection
cities_ref = db.collection("cities")

# Create a query against the collection
query_ref = cities_ref.where(filter=FieldFilter("state", "==", "CA"))
Python
(Async)
# Create a reference to the cities collection
cities_ref = db.collection("cities")

# Create a query against the collection
query_ref = cities_ref.where(filter=FieldFilter("state", "==", "CA"))
C++
CollectionReference cities_ref = db->Collection("cities");
// Create a query against the collection.
Query query_ca =
    cities_ref.WhereEqualTo("state", FieldValue::String("CA"));
Node.js
// Create a reference to the cities collection
const citiesRef = db.collection('cities');

// Create a query against the collection
const queryRef = citiesRef.where('state', '==', 'CA');
Go
query := client.Collection("cities").Where("state", "==", "CA")
PHP
$citiesRef = $db->collection('samples/php/cities');
$query = $citiesRef->where('state', '=', 'CA');
$snapshot = $query->documents();
foreach ($snapshot as $document) {
    printf('Document %s returned by query state=CA' . PHP_EOL, $document->id());
}
Unity
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereEqualTo("State", "CA");
query.GetSnapshotAsync().ContinueWithOnMainThread((querySnapshotTask) =>
{
    foreach (DocumentSnapshot documentSnapshot in querySnapshotTask.Result.Documents)
    {
        Debug.Log(String.Format("Document {0} returned by query State=CA", documentSnapshot.Id));
    } 
});
C#
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereEqualTo("State", "CA");
QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
{
    Console.WriteLine("Document {0} returned by query State=CA", documentSnapshot.Id);
}
Ruby
cities_ref = firestore.col collection_path

query = cities_ref.where "state", "=", "CA"

query.get do |city|
  puts "Document #{city.document_id} returned by query state=CA."
end

The following query returns all the capital cities:

Web version 9

import { collection, query, where } from "firebase/firestore";
const citiesRef = collection(db, "cities");

const q = query(citiesRef, where("capital", "==", true));

Web version 8

var citiesRef = db.collection("cities");

var query = citiesRef.where("capital", "==", true);
Swift
Note: This product is not available on watchOS and App Clip targets.
let capitalCities = db.collection("cities").whereField("capital", isEqualTo: true)
Objective-C
Note: This product is not available on watchOS and App Clip targets.
FIRQuery *capitalCities =
    [[self.db collectionWithPath:@"cities"] queryWhereField:@"capital" isEqualTo:@YES];
Kotlin
Android
val capitalCities = db.collection("cities").whereEqualTo("capital", true)
Java
Android
Query capitalCities = db.collection("cities").whereEqualTo("capital", true);

Dart

final capitalcities =
    db.collection("cities").where("capital", isEqualTo: true);
Java
// Create a reference to the cities collection
CollectionReference cities = db.collection("cities");
// Create a query against the collection.
Query query = cities.whereEqualTo("capital", true);
// retrieve  query results asynchronously using query.get()
ApiFuture<QuerySnapshot> querySnapshot = query.get();

for (DocumentSnapshot document : querySnapshot.get().getDocuments()) {
  System.out.println(document.getId());
}
Python
cities_ref = db.collection("cities")

query = cities_ref.where(filter=FieldFilter("capital", "==", True))
Python
(Async)
cities_ref = db.collection("cities")

query = cities_ref.where(filter=FieldFilter("capital", "==", True))
C++
Query capital_cities = db->Collection("cities").WhereEqualTo(
    "capital", FieldValue::Boolean(true));
Node.js
// Create a reference to the cities collection
const citiesRef = db.collection('cities');

// Create a query against the collection
const allCapitalsRes = citiesRef.where('capital', '==', true);
Go
query := client.Collection("cities").Where("capital", "==", true)
PHP
$citiesRef = $db->collection('samples/php/cities');
$query = $citiesRef->where('capital', '=', true);
$snapshot = $query->documents();
foreach ($snapshot as $document) {
    printf('Document %s returned by query capital=true' . PHP_EOL, $document->id());
}
Unity
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereEqualTo("Capital", true);
query.GetSnapshotAsync().ContinueWithOnMainThread((querySnapshotTask) =>
{
    foreach (DocumentSnapshot documentSnapshot in querySnapshotTask.Result.Documents)
    {
        Debug.Log(String.Format("Document {0} returned by query Capital=true", documentSnapshot.Id));
    } 
});
C#
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereEqualTo("Capital", true);
QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
{
    Console.WriteLine("Document {0} returned by query Capital=true", documentSnapshot.Id);
}
Ruby
cities_ref = firestore.col collection_path

query = cities_ref.where "capital", "=", true

query.get do |city|
  puts "Document #{city.document_id} returned by query capital=true."
end

Execute a query

After creating a query object, use the get() function to retrieve the results:

Web version 9

import { collection, query, where, getDocs } from "firebase/firestore";

const q = query(collection(db, "cities"), where("capital", "==", true));

const querySnapshot = await getDocs(q);
querySnapshot.forEach((doc) => {
  // doc.data() is never undefined for query doc snapshots
  console.log(doc.id, " => ", doc.data());
});

Web version 8

db.collection("cities").where("capital", "==", true)
    .get()
    .then((querySnapshot) => {
        querySnapshot.forEach((doc) => {
            // doc.data() is never undefined for query doc snapshots
            console.log(doc.id, " => ", doc.data());
        });
    })
    .catch((error) => {
        console.log("Error getting documents: ", error);
    });
Swift
Note: This product is not available on watchOS and App Clip targets.
do {
  let querySnapshot = try await db.collection("cities").whereField("capital", isEqualTo: true)
    .getDocuments()
  for document in querySnapshot.documents {
    print("\(document.documentID) => \(document.data())")
  }
} catch {
  print("Error getting documents: \(error)")
}
Objective-C
Note: This product is not available on watchOS and App Clip targets.
[[[self.db collectionWithPath:@"cities"] queryWhereField:@"capital" isEqualTo:@(YES)]
    getDocumentsWithCompletion:^(FIRQuerySnapshot *snapshot, NSError *error) {
      if (error != nil) {
        NSLog(@"Error getting documents: %@", error);
      } else {
        for (FIRDocumentSnapshot *document in snapshot.documents) {
          NSLog(@"%@ => %@", document.documentID, document.data);
        }
      }
    }];
Kotlin
Android
db.collection("cities")
    .whereEqualTo("capital", true)
    .get()
    .addOnSuccessListener { documents ->
        for (document in documents) {
            Log.d(TAG, "${document.id} => ${document.data}")
        }
    }
    .addOnFailureListener { exception ->
        Log.w(TAG, "Error getting documents: ", exception)
    }
Java
Android
db.collection("cities")
        .whereEqualTo("capital", true)
        .get()
        .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
            @Override
            public void onComplete(@NonNull Task<QuerySnapshot> task) {
                if (task.isSuccessful()) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        Log.d(TAG, document.getId() + " => " + document.getData());
                    }
                } else {
                    Log.d(TAG, "Error getting documents: ", task.getException());
                }
            }
        });

Dart

db.collection("cities").where("capital", isEqualTo: true).get().then(
  (querySnapshot) {
    print("Successfully completed");
    for (var docSnapshot in querySnapshot.docs) {
      print('${docSnapshot.id} => ${docSnapshot.data()}');
    }
  },
  onError: (e) => print("Error completing: $e"),
);
Java
// asynchronously retrieve multiple documents
ApiFuture<QuerySnapshot> future = db.collection("cities").whereEqualTo("capital", true).get();
// future.get() blocks on response
List<QueryDocumentSnapshot> documents = future.get().getDocuments();
for (DocumentSnapshot document : documents) {
  System.out.println(document.getId() + " => " + document.toObject(City.class));
}
Python
# Note: Use of CollectionRef stream() is prefered to get()
docs = (
    db.collection("cities")
    .where(filter=FieldFilter("capital", "==", True))
    .stream()
)

for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
Python
(Async)
# Note: Use of CollectionRef stream() is prefered to get()
docs = (
    db.collection("cities")
    .where(filter=FieldFilter("capital", "==", True))
    .stream()
)

async for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
C++
db->Collection("cities")
    .WhereEqualTo("capital", FieldValue::Boolean(true))
    .Get()
    .OnCompletion([](const Future<QuerySnapshot>& future) {
      if (future.error() == Error::kErrorOk) {
        for (const DocumentSnapshot& document :
             future.result()->documents()) {
          std::cout << document << std::endl;
        }
      } else {
        std::cout << "Error getting documents: " << future.error_message()
                  << std::endl;
      }
    });
Node.js
const citiesRef = db.collection('cities');
const snapshot = await citiesRef.where('capital', '==', true).get();
if (snapshot.empty) {
  console.log('No matching documents.');
  return;
}  

snapshot.forEach(doc => {
  console.log(doc.id, '=>', doc.data());
});
Go

import (
	"context"
	"fmt"

	"cloud.google.com/go/firestore"
	"google.golang.org/api/iterator"
)

func multipleDocs(ctx context.Context, client *firestore.Client) error {
	fmt.Println("All capital cities:")
	iter := client.Collection("cities").Where("capital", "==", true).Documents(ctx)
	for {
		doc, err := iter.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return err
		}
		fmt.Println(doc.Data())
	}
	return nil
}
PHP

PHP

To authenticate to Firestore, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

$citiesRef = $db->collection('samples/php/cities');
$query = $citiesRef->where('capital', '=', true);
$documents = $query->documents();
foreach ($documents as $document) {
    if ($document->exists()) {
        printf('Document data for document %s:' . PHP_EOL, $document->id());
        print_r($document->data());
        printf(PHP_EOL);
    } else {
        printf('Document %s does not exist!' . PHP_EOL, $document->id());
    }
}
Unity
Query capitalQuery = db.Collection("cities").WhereEqualTo("Capital", true);
capitalQuery.GetSnapshotAsync().ContinueWithOnMainThread(task => {
  QuerySnapshot capitalQuerySnapshot = task.Result;
  foreach (DocumentSnapshot documentSnapshot in capitalQuerySnapshot.Documents) {
    Debug.Log(String.Format("Document data for {0} document:", documentSnapshot.Id));
    Dictionary<string, object> city = documentSnapshot.ToDictionary();
    foreach (KeyValuePair<string, object> pair in city) {
      Debug.Log(String.Format("{0}: {1}", pair.Key, pair.Value));
    }

    // Newline to separate entries
    Debug.Log("");
  };
});
C#
Query capitalQuery = db.Collection("cities").WhereEqualTo("Capital", true);
QuerySnapshot capitalQuerySnapshot = await capitalQuery.GetSnapshotAsync();
foreach (DocumentSnapshot documentSnapshot in capitalQuerySnapshot.Documents)
{
    Console.WriteLine("Document data for {0} document:", documentSnapshot.Id);
    Dictionary<string, object> city = documentSnapshot.ToDictionary();
    foreach (KeyValuePair<string, object> pair in city)
    {
        Console.WriteLine("{0}: {1}", pair.Key, pair.Value);
    }
    Console.WriteLine("");
}
Ruby
cities_ref = firestore.col collection_path

query = cities_ref.where "capital", "=", true

query.get do |city|
  puts "#{city.document_id} data: #{city.data}."
end

See Get Data for more information on retrieving query results. You can also add a listener to a query to get the current results and listen for future updates.

Query operators

The where() method takes three parameters: a field to filter on, a comparison operator, and a value. Firestore supports the following comparison operators:

For example:

Web version 9

const stateQuery = query(citiesRef, where("state", "==", "CA"));
const populationQuery = query(citiesRef, where("population", "<", 100000));
const nameQuery = query(citiesRef, where("name", ">=", "San Francisco"));

Web version 8

const stateQuery = citiesRef.where("state", "==", "CA");
const populationQuery = citiesRef.where("population", "<", 100000);
const nameQuery = citiesRef.where("name", ">=", "San Francisco");
Swift
Note: This product is not available on watchOS and App Clip targets.
let stateQuery = citiesRef.whereField("state", isEqualTo: "CA")
let populationQuery = citiesRef.whereField("population", isLessThan: 100000)
let nameQuery = citiesRef.whereField("name", isGreaterThanOrEqualTo: "San Francisco")
Objective-C
Note: This product is not available on watchOS and App Clip targets.
FIRQuery *stateQuery = [citiesRef queryWhereField:@"state" isEqualTo:@"CA"];
FIRQuery *populationQuery = [citiesRef queryWhereField:@"population" isLessThan:@100000];
FIRQuery *nameQuery = [citiesRef queryWhereField:@"name" isGreaterThanOrEqualTo:@"San Francisco"];
Kotlin
Android
val stateQuery = citiesRef.whereEqualTo("state", "CA")
val populationQuery = citiesRef.whereLessThan("population", 100000)
val nameQuery = citiesRef.whereGreaterThanOrEqualTo("name", "San Francisco")
Java
Android
Query stateQuery = citiesRef.whereEqualTo("state", "CA");
Query populationQuery = citiesRef.whereLessThan("population", 100000);
Query nameQuery = citiesRef.whereGreaterThanOrEqualTo("name", "San Francisco");

Dart

final citiesRef = db.collection("cities");
final stateQuery = citiesRef.where("state", isEqualTo: "CA");
final populationQuery = citiesRef.where("population", isLessThan: 100000);
final nameQuery = citiesRef.where("name", isEqualTo: "San Francisco");
Java
Query stateQuery = cities.whereEqualTo("state", "CA");
Query populationQuery = cities.whereLessThan("population", 1000000L);
Query nameQuery = cities.whereGreaterThanOrEqualTo("name", "San Francisco");
Python
cities_ref = db.collection("cities")

cities_ref.where(filter=FieldFilter("state", "==", "CA"))
cities_ref.where(filter=FieldFilter("population", "<", 1000000))
cities_ref.where(filter=FieldFilter("name", ">=", "San Francisco"))
Python
(Async)
cities_ref = db.collection("cities")

cities_ref.where(filter=FieldFilter("state", "==", "CA"))
cities_ref.where(filter=FieldFilter("population", "<", 1000000))
cities_ref.where(filter=FieldFilter("name", ">=", "San Francisco"))
C++
cities_ref.WhereEqualTo("state", FieldValue::String("CA"));
cities_ref.WhereLessThan("population", FieldValue::Integer(100000));
cities_ref.WhereGreaterThanOrEqualTo("name",
                                     FieldValue::String("San Francisco"));
Node.js
const stateQueryRes = await citiesRef.where('state', '==', 'CA').get();
const populationQueryRes = await citiesRef.where('population', '<', 1000000).get();
const nameQueryRes = await citiesRef.where('name', '>=', 'San Francisco').get();
Go
countryQuery := cities.Where("state", "==", "CA")
popQuery := cities.Where("population", "<", 1000000)
cityQuery := cities.Where("name", ">=", "San Francisco")
PHP
$stateQuery = $citiesRef->where('state', '=', 'CA');
$populationQuery = $citiesRef->where('population', '>', 1000000);
$nameQuery = $citiesRef->where('name', '>=', 'San Francisco');
Unity
Query stateQuery = citiesRef.WhereEqualTo("State", "CA");
Query populationQuery = citiesRef.WhereGreaterThan("Population", 1000000);
Query nameQuery = citiesRef.WhereGreaterThanOrEqualTo("Name", "San Francisco");
C#
CollectionReference citiesRef = db.Collection("cities");
Query stateQuery = citiesRef.WhereEqualTo("State", "CA");
Query populationQuery = citiesRef.WhereGreaterThan("Population", 1000000);
Query nameQuery = citiesRef.WhereGreaterThanOrEqualTo("Name", "San Francisco");
Ruby
state_query      = cities_ref.where "state", "=", "CA"
population_query = cities_ref.where "population", ">", 1_000_000
name_query       = cities_ref.where "name", ">=", "San Francisco"

Not equal (!=)

Use the not equal (!=) operator to return documents where the given field exists and does not match the comparison value. For example:

Web version 9

const notCapitalQuery = query(citiesRef, where("capital", "!=", false));

Web version 8

citiesRef.where("capital", "!=", false);
Swift
Note: This product is not available on watchOS and App Clip targets.
let notEqualQuery = citiesRef.whereField("capital", isNotEqualTo: false)
Objective-C
Note: This product is not available on watchOS and App Clip targets.
query = [citiesRef queryWhereField:@"capital" isNotEqualTo:@NO];
Kotlin
Android
val notCapitalQuery = citiesRef.whereNotEqualTo("capital", false)
Java
Android
Query notCapitalQuery = citiesRef.whereNotEqualTo("capital", false);

Dart

final citiesRef = db.collection("cities");
final notCapitals = citiesRef.where("capital", isNotEqualTo: true);
Java
CollectionReference citiesRef = db.collection("cities");

Query query = citiesRef.whereNotEqualTo("capital", false);
Python
// Snippet not yet available
C++
cities_ref.WhereNotEqualTo("capital", FieldValue::Boolean(false));
Node.js
const capitalNotFalseRes = await citiesRef.where('capital', '!=', false).get();
Go
// Snippet not yet available
PHP
$stateQuery = $citiesRef->where('capital', '!=', false);
Unity
Query query = citiesRef.WhereNotEqualTo("capital", false);
Query query = citiesRef.WhereNotEqualTo("capital", false);
C#
// Snippet not yet available
Ruby
cities_ref = firestore.col collection_path
query = cities_ref.where "capital", "!=", false

This query returns every city document where the capital field exists with a value other than false or null. This includes city documents where the capital field value equals true or any non-boolean value besides null.

This query does not return city documents where the capital field does not exist. Not-equal (!=) and not-in queries exclude documents where the given field does not exist.

A field exists when it's set to any value, including an empty string (""), null, and NaN (not a number). Note that null field values do not match != clauses, because x != null evaluates to undefined.

Limitations

Note the following limitations for != queries:

  • Only documents where the given field exists can match the query.
  • You can't combine not-in and != in a compound query.

Array membership

You can use the array-contains operator to filter based on array values. For example:

Web version 9

import { query, where } from "firebase/firestore";  
const q = query(citiesRef, where("regions", "array-contains", "west_coast"));

Web version 8

citiesRef.where("regions", "array-contains", "west_coast");
Swift
Note: This product is not available on watchOS and App Clip targets.
citiesRef
  .whereField("regions", arrayContains: "west_coast")
Objective-C
Note: This product is not available on watchOS and App Clip targets.
[citiesRef queryWhereField:@"state" arrayContains:@"west_coast"];
Kotlin
Android
val citiesRef = db.collection("cities")

citiesRef.whereArrayContains("regions", "west_coast")
Java
Android
CollectionReference citiesRef = db.collection("cities");

citiesRef.whereArrayContains("regions", "west_coast");

Dart

final citiesRef = db.collection("cities");
final westCoastcities =
    citiesRef.where("regions", arrayContains: "west_coast");
Java
CollectionReference citiesRef = db.collection("cities");
Query westCoastQuery = citiesRef.whereArrayContains("regions", "west_coast");
Python
cities_ref = db.collection("cities")

query = cities_ref.where(
    filter=FieldFilter("regions", "array_contains", "west_coast")
)
Python
(Async)
cities_ref = db.collection("cities")

query = cities_ref.where(
    filter=FieldFilter("regions", "array_contains", "west_coast")
)
C++
CollectionReference cities_ref = db->Collection("cities");

cities_ref.WhereArrayContains("region", FieldValue::String("west_coast"));
Node.js
const westCoastCities = citiesRef.where('regions', 'array-contains',
  'west_coast').get();
Go
query := cities.Where("regions", "array-contains", "west_coast").Documents(ctx)
PHP
$containsQuery = $citiesRef->where('regions', 'array-contains', 'west_coast');
Unity
CollectionReference citiesRef = db.Collection("cities");
Query arrayContainsQuery = citiesRef.WhereArrayContains("region", "west_coast");
C#
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereArrayContains("Regions", "west_coast");
Ruby
cities_ref = firestore.col collection_path
cities = cities_ref.where "regions", "array-contains", "west_coast"

This query returns every city document where the regions field is an array that contains west_coast. If the array has multiple instances of the value you query on, the document is included in the results only once.

You can use at most one array-contains clause per disjunction (or group). You can't combine array-contains with array-contains-any in the same disjunction.

in, not-in, and array-contains-any

Use the in operator to combine up to 30 equality (==) clauses on the same field with a logical OR. An in query returns documents where the given field matches any of the comparison values. For example:

Web version 9

import { query, where } from "firebase/firestore";

const q = query(citiesRef, where('country', 'in', ['USA', 'Japan']));

Web version 8

citiesRef.where('country', 'in', ['USA', 'Japan']);
Swift
Note: This product is not available on watchOS and App Clip targets.
let citiesRef = db.collection("cities")

citiesRef.whereField("country", in: ["USA", "Japan"])
Objective-C
Note: This product is not available on watchOS and App Clip targets.
FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];

[citiesRef queryWhereField:@"country" in:@[@"USA", @"Japan"]];
Kotlin
Android
val citiesRef = db.collection("cities")

citiesRef.whereIn("country", listOf("USA", "Japan"))
Java
Android
CollectionReference citiesRef = db.collection("cities");

citiesRef.whereIn("country", Arrays.asList("USA", "Japan"));

Dart

final citiesRef = db.collection("cities");
final cities = citiesRef.where("country", whereIn: ["USA", "Japan"]);
Java
CollectionReference citiesRef = db.collection("cities");

Query query = citiesRef.whereIn("country", Arrays.asList("USA", "Japan"));
Python
cities_ref = db.collection("cities")

query = cities_ref.where(filter=FieldFilter("country", "in", ["USA", "Japan"]))
return query
Python
(Async)
cities_ref = db.collection("cities")

query = cities_ref.where(filter=FieldFilter("country", "in", ["USA", "Japan"]))
return query
C++
CollectionReference cities_ref = db->Collection("cities");

cities_ref.WhereIn("country", std::vector<FieldValue> {
  FieldValue::String("USA"),
  FieldValue::String("Japan")
});
Node.js
const usaOrJapan = await citiesRef.where('country', 'in', ['USA', 'Japan']).get();
Go
cities := client.Collection("cities")
query := cities.Where("country", "in", []string{"USA", "Japan"}).Documents(ctx)
PHP
$rangeQuery = $citiesRef->where('country', 'in', ['USA', 'Japan']);
Unity
CollectionReference citiesRef = db.Collection("cities");
List countriesList = new List<object>() {"USA", "Japan"};

Query whereInQuery = citiesRef.WhereIn("country", countriesList);
C#
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereIn("Country", new[] { "USA", "Japan" });
Ruby
cities_ref = firestore.col collection_path
usr_or_japan = cities_ref.where "country", "in", ["USA", "Japan"]

This query returns every city document where the country field is set to USA or Japan. From the example data, this includes the SF, LA, DC, and TOK documents.

not-in

Use the not-in operator to combine up to 10 not equal (!=) clauses on the same field with a logical AND. A not-in query returns documents where the given field exists, is not null, and does not match any of the comparison values. For example:

Web version 9

import { query, where } from "firebase/firestore";

const q = query(citiesRef, where('country', 'not-in', ['USA', 'Japan']));

Web version 8

citiesRef.where('country', 'not-in', ['USA', 'Japan']);
Swift
Note: This product is not available on watchOS and App Clip targets.
citiesRef.whereField("country", notIn: ["USA", "Japan"])
Objective-C
Note: This product is not available on watchOS and App Clip targets.
[citiesRef queryWhereField:@"country" notIn:@[@"USA", @"Japan"]];
Kotlin
Android
citiesRef.whereNotIn("country", listOf("USA", "Japan"))
Java
Android
citiesRef.whereNotIn("country", Arrays.asList("USA", "Japan"));

Dart

final citiesRef = db.collection("cities");
final cities = citiesRef.where("country", whereNotIn: ["USA", "Japan"]);
Java
CollectionReference citiesRef = db.collection("cities");

Query query = citiesRef.whereNotIn("country", Arrays.asList("USA", "Japan"));
Python
// Snippet not yet available
C++
cities_ref.WhereNotIn("country", std::vector<FieldValue> {
  FieldValue::String("USA"),
  FieldValue::String("Japan")
});
Node.js
const notUsaOrJapan = await citiesRef.where('country', 'not-in', ['USA', 'Japan']).get();
Go
// Snippet not yet available
PHP
$stateQuery = $citiesRef->where(
    'country',
    \Google\Cloud\Firestore\V1\StructuredQuery\FieldFilter\Operator::NOT_IN,
    ['USA', 'Japan']
);
Unity
Query query = citiesRef.WhereNotIn(new FieldPath("country"), new List<string>{"USA", "Japan"});
Query query = citiesRef.WhereNotIn("country", new List<object>(){"USA", "Japan"});
C#
// Snippet not yet available
Ruby
cities_ref = firestore.col collection_path
usr_or_japan = cities_ref.where "country", "not_in", ["USA", "Japan"]

This query returns every city document where the country field exists and is not set to USA, Japan, or null. From the example data, this includes the London and Hong Kong documents.

not-in queries exclude documents where the given field does not exist. A field exists when it's set to any value, including an empty string (""), null, and NaN (not a number). Note that x != null evaluates to undefined. A not-in query with null as one of the comparison values does not match any documents.

array-contains-any

Use the array-contains-any operator to combine up to 30 array-contains clauses on the same field with a logical OR. An array-contains-any query returns documents where the given field is an array that contains one or more of the comparison values:

Web version 9

import { query, where } from "firebase/firestore";  

const q = query(citiesRef, 
  where('regions', 'array-contains-any', ['west_coast', 'east_coast']));

Web version 8

citiesRef.where('regions', 'array-contains-any',
    ['west_coast', 'east_coast']);
Swift
Note: This product is not available on watchOS and App Clip targets.
let citiesRef = db.collection("cities")
citiesRef.whereField("regions", arrayContainsAny: ["west_coast", "east_coast"])
Objective-C
Note: This product is not available on watchOS and App Clip targets.
FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];

[citiesRef queryWhereField:@"regions" arrayContainsAny:@[@"west_coast", @"east_coast"]];
Kotlin
Android
val citiesRef = db.collection("cities")

citiesRef.whereArrayContainsAny("regions", listOf("west_coast", "east_coast"))
Java
Android
CollectionReference citiesRef = db.collection("cities");

citiesRef.whereArrayContainsAny("regions", Arrays.asList("west_coast", "east_coast"));

Dart

final citiesRef = db.collection("cities");
final cities = citiesRef
    .where("regions", arrayContainsAny: ["west_coast", "east_coast"]);
Java
CollectionReference citiesRef = db.collection("cities");

Query query =
    citiesRef.whereArrayContainsAny("regions", Arrays.asList("west_coast", "east_coast"));
Python
cities_ref = db.collection("cities")

query = cities_ref.where(
    filter=FieldFilter(
        "regions", "array_contains_any", ["west_coast", "east_coast"]
    )
)
return query
Python
(Async)
cities_ref = db.collection("cities")

query = cities_ref.where(
    filter=FieldFilter(
        "regions", "array_contains_any", ["west_coast", "east_coast"]
    )
)
return query
C++
CollectionReference cities_ref = db->Collection("cities");

cities_ref.WhereArrayContainsAny("region", std::vector<FieldValue> {
  FieldValue::String("west_coast"),
  FieldValue::String("east_coast")
});
Node.js
const coastalCities = await citiesRef.where('regions', 'array-contains-any',
    ['west_coast', 'east_coast']).get();
Go
cities := client.Collection("cities")
query := cities.Where("regions", "array-contains-any", []string{"west_coast", "east_coast"}).Documents(ctx)
PHP
$containsQuery = $citiesRef->where('regions', 'array-contains-any', ['west_coast', 'east_coast']);
Unity
Query query = citiesRef.WhereArrayContainsAny(
                         "regions",
                         new List<object>()
                         {
                            new List<object>(){"west_coast"},
                            new List<object>(){"east_coast"}});
C#
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereArrayContainsAny("Regions", new[] { "west_coast", "east_coast" });
Ruby
cities_ref = firestore.col collection_path
costal_cities = cities_ref.where "regions", "array-contains-any", ["west_coast", "east_coast"]

This query returns every city document where the regions field is an array that contains west_coast or east_coast. From the example data, this includes the SF, LA, and DC documents.

Results from array-contains-any are de-duped. Even if a document's array field matches more than one of the comparison values, the result set includes that document only once.

array-contains-any always filters by the array data type. For example, the query above would not return a city document where instead of an array, the regions field is the string west_coast.

You can use an array value as a comparison value for in, but unlike array-contains-any, the clause matches for an exact match of array length, order, and values. For example:

Web version 9

import { query, where } from "firebase/firestore";  

const q = query(citiesRef, where('regions', 'in', [['west_coast'], ['east_coast']]));

Web version 8

citiesRef.where('regions', 'in',
    [['west_coast'], ['east_coast']]);
Swift
Note: This product is not available on watchOS and App Clip targets.
citiesRef.whereField("regions", in: [["west_coast"], ["east_coast"]])
Objective-C
Note: This product is not available on watchOS and App Clip targets.
[citiesRef queryWhereField:@"regions" in:@[@[@"west_coast"], @[@"east_coast"]]];
Kotlin
Android
citiesRef.whereIn("regions", listOf(arrayOf("west_coast"), arrayOf("east_coast")))
Java
Android
citiesRef.whereIn("regions", Arrays.asList(new String[]{"west_coast"}, new String[]{"east_coast"}));

Dart

final citiesRef = db.collection("cities");
final cities = citiesRef.where("regions", whereIn: [
  ["west_coast"],
  ["east_coast"]
]);
Java
CollectionReference citiesRef = db.collection("cities");

Query query =
    citiesRef.whereIn(
        "regions", Arrays.asList(Arrays.asList("west_coast"), Arrays.asList("east_coast")));
Python
cities_ref = db.collection("cities")

query = cities_ref.where(
    filter=FieldFilter("regions", "in", [["west_coast"], ["east_coast"]])
)
return query
Python
(Async)
cities_ref = db.collection("cities")

query = cities_ref.where(
    filter=FieldFilter("regions", "in", [["west_coast"], ["east_coast"]])
)
return query
C++
cities_ref.WhereIn("region", std::vector<FieldValue> {
  FieldValue::String("west_coast"),
  FieldValue::String("east_coast")
});
Node.js
const exactlyOneCoast = await citiesRef.where('regions', 'in',
    [['west_coast', 'east_coast']]).get();
Go
cities := client.Collection("cities")
query := cities.Where("regions", "in", [][]string{{"west_coast"}, {"east_coast"}}).Documents(ctx)
PHP
$rangeQuery = $citiesRef->where('regions', 'in', [['west_coast'], ['east_coast']]);
Unity
Query query = citiesRef.WhereIn(new FieldPath("regions"), new List<string>{"west_coast", "east_coast"});
C#
CollectionReference citiesRef = db.Collection("cities");
Query query = citiesRef.WhereIn("Regions",
    new[] { new[] { "west_coast" }, new[] { "east_coast" } });
Ruby
cities_ref = firestore.col collection_path
exactly_one_cost = cities_ref.where "regions", "in", [["west_coast"], ["east_coast"]]

This query returns every city document where the regions field is an array that contains exactly one element of either west_coast or east_coast. From the example data, only the DC document qualifies with its regions field of ["east_coast"]. The SF document, however, does not match because its regions field is ["west_coast", "norcal"].

Limitations

Note the following limitations for in, not-in, and array-contains-any:

  • Firestore provides support for logical OR queries through the or, in, and array-contains-any operators. These queries are limited to 30 disjunctions based on the query's disjunctive normal form.
  • You can use at most one array-contains clause per disjunction (or group). You can't combine array-contains with array-contains-any in the same disjunction.
  • You can't combine not-in with not equals !=.
  • not-in supports up to 10 comparison values.

Compound (AND) queries

You can combine constraints with a logical AND by chaining multiple equality operators (== or array-contains). However, you must create a composite index to combine equality operators with the inequality operators, <, <=, >, and !=.

Web version 9

import { query, where } from "firebase/firestore";  

const q1 = query(citiesRef, where("state", "==", "CO"), where("name", "==", "Denver"));
const q2 = query(citiesRef, where("state", "==", "CA"), where("population", "<", 1000000));

Web version 8

const q1 = citiesRef.where("state", "==", "CO").where("name", "==", "Denver");
const q2 = citiesRef.where("state", "==", "CA").where("population", "<", 1000000);
Swift
Note: This product is not available on watchOS and App Clip targets.
citiesRef
  .whereField("state", isEqualTo: "CO")
  .whereField("name", isEqualTo: "Denver")
citiesRef
  .whereField("state", isEqualTo: "CA")
  .whereField("population", isLessThan: 1000000)
Objective-C
Note: This product is not available on watchOS and App Clip targets.
[[citiesRef queryWhereField:@"state" isEqualTo:@"CO"]
    queryWhereField:@"name" isGreaterThanOrEqualTo:@"Denver"];
[[citiesRef queryWhereField:@"state" isEqualTo:@"CA"]
    queryWhereField:@"population" isLessThan:@1000000];
Kotlin
Android
citiesRef.whereEqualTo("state", "CO").whereEqualTo("name", "Denver")
citiesRef.whereEqualTo("state", "CA").whereLessThan("population", 1000000)
Java
Android
citiesRef.whereEqualTo("state", "CO").whereEqualTo("name", "Denver");
citiesRef.whereEqualTo("state", "CA").whereLessThan("population", 1000000);

Dart

final citiesRef = db.collection("cities");
citiesRef
    .where("state", isEqualTo: "CO")
    .where("name", isEqualTo: "Denver");
citiesRef
    .where("state", isEqualTo: "CA")
    .where("population", isLessThan: 1000000);
Java
Query chainedQuery1 = cities.whereEqualTo("state", "CO").whereEqualTo("name", "Denver");
Python
cities_ref = db.collection("cities")

denver_query = cities_ref.where(filter=FieldFilter("state", "==", "CO")).where(
    filter=FieldFilter("name", "==", "Denver")
)
large_us_cities_query = cities_ref.where(
    filter=FieldFilter("state", "==", "CA")
).where(filter=FieldFilter("population", ">", 1000000))
Python
(Async)
cities_ref = db.collection("cities")

denver_query = cities_ref.where(filter=FieldFilter("state", "==", "CO")).where(
    filter=FieldFilter("name", "==", "Denver")
)
large_us_cities_query = cities_ref.where(
    filter=FieldFilter("state", "==", "CA")
).where(filter=FieldFilter("population", ">", 1000000))
C++
cities_ref.WhereEqualTo("state", FieldValue::String("CO"))
    .WhereEqualTo("name", FieldValue::String("Denver"));
cities_ref.WhereEqualTo("state", FieldValue::String("CA"))
    .WhereLessThan("population", FieldValue::Integer(1000000));
Node.js
citiesRef.where('state', '==', 'CO').where('name', '==', 'Denver');
citiesRef.where('state', '==', 'CA').where('population', '<', 1000000);
Go
denverQuery := cities.Where("name", "==", "Denver").Where("state", "==", "CO")
caliQuery := cities.Where("state", "==", "CA").Where("population", "<=", 1000000)
query := cities.Where("country", "==", "USA").Where("population", ">", 5000000)
PHP
$chainedQuery = $citiesRef
    ->where('state', '=', 'CA')
    ->where('name', '=', 'San Francisco');
Unity
Query chainedQuery = citiesRef
    .WhereEqualTo("State", "CA")
    .WhereEqualTo("Name", "San Francisco");
C#
CollectionReference citiesRef = db.Collection("cities");
Query chainedQuery = citiesRef
    .WhereEqualTo("State", "CA")
    .WhereEqualTo("Name", "San Francisco");
Ruby
chained_query = cities_ref.where("state", "=", "CA").where("name", "=", "San Francisco")

OR queries

You can combine constraints with a logical OR. For example:

Web version 9

const q = query(citiesRef,
  or(where('capital', '==', true),
     where('population', '>=', 1000000)
  )
);
  

Web version 8

Not available.

Swift
let query = db.collection("cities").whereFilter(Filter.orFilter([
                Filter.whereField("capital", isEqualTo: true),
                Filter.whereField("population", isGreaterThanOrEqualTo: 1000000);
            ]))
  
Objective-C
  FIRCollectionReference *collection = [self.db collectionWithPath:@"cities"];
  FIRQuery *query = [collection queryWhereFilter:[FIRFilter orFilterWithFilters:@[
      [FIRFilter filterWhereField:@"capital" isEqualTo:@YES],
      [FIRFilter filterWhereField:@"population" isGreaterThanOrEqualTo:@1000000]
  ]]];
  
Kotlin
Android
val query = collection.where(Filter.or(
        Filter.equalTo("capital", true),
        Filter.greaterThanOrEqualTo("population", 1000000)
))
  
Java
Android
Query query = collection.where(Filter.or(
        Filter.equalTo("capital", true),
        Filter.greaterThanOrEqualTo("population", 1000000)
));
  

Dart

var query = db.collection("cities").where(
      Filter.or(
        Filter("capital", isEqualTo: true),
        Filter("population", isGreaterThan: 1000000),
      ),
    );
Java

Snippet not available.

Python
from google.cloud.firestore_v1.base_query import FieldFilter, Or

col_ref = client.collection("cities")
# Execute the query
query = col_ref.where(
    filter=Or(
        [
            FieldFilter("capital", "==", True),
            FieldFilter("population", ">", 1_000_000),
        ]
    )
)
docs = query.stream()
Python
(Async)

Snippet not available.

C++

Snippet not available.

Node.js
const bigCities = await citiesRef
  .where(
    Filter.or(
      Filter.where('capital', '==', true),
      Filter.where('population', '>=', 1000000)
    )
  )
  .get();
Go
import (
	"context"
	"fmt"
	"io"

	firestore "cloud.google.com/go/firestore"
	"google.golang.org/api/iterator"
)

func queryFilterOr(w io.Writer, projectId string) error {
	// Instantiate a client
	ctx := context.Background()
	client, err := firestore.NewClient(ctx, projectId)
	if err != nil {
		return err
	}
	// always be sure to close the client to release resources
	defer client.Close()

	q1 := firestore.PropertyFilter{
		Path:     "birthYear",
		Operator: "==",
		Value:    1906,
	}

	q2 := firestore.PropertyFilter{
		Path:     "birthYear",
		Operator: "==",
		Value:    1815,
	}

	orFilter := firestore.OrFilter{
		Filters: []firestore.EntityFilter{q1, q2},
	}

	orQuery := client.Collection("users").WhereEntity(orFilter)
	it := orQuery.Documents(ctx)
	if err != nil {
		return err
	}

	fmt.Fprint(w, "Individual documents:\n")
	for {
		doc, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return fmt.Errorf("documents iterator: %w", err)
		}
		fmt.Fprintf(w, "%s: %s", doc.Ref.ID, doc.Data()["birthYear"])
	}

	return nil
}
PHP

Snippet not available.

Unity
Query query = citiesRef.Where(Filter.Or(
        Filter.EqualTo("State", "CA"),
        Filter.GreaterThanOrEqualTo("population", 1000000)
));
query.GetSnapshotAsync().ContinueWithOnMainThread((querySnapshotTask) =>
{
    foreach (DocumentSnapshot documentSnapshot in querySnapshotTask.Result.Documents)
    {
        Debug.Log(String.Format("Document {0} returned by query State=CA or population >= {1}", documentSnapshot.Id, 1000000));
    } 
});
C#

Snippet not available.

Ruby

Snippet not available.

Firestore uses your composite indexes to serve OR queries. If your indexes do not support the query, Firestore suggests additional indexes for your database.

You can combine OR queries with compound queries to filter on combinations of OR and AND operations. For example:

Web version 9

const q = query(collection(db, "cities"), and(
  where('state', '==', 'CA'),   
  or(
    where('capital', '==', true),
    where('population', '>=', 1000000)
  )
));

Web version 8

Not available.

Swift
Note: This product is not available on watchOS and App Clip targets.
let query = db.collection("cities").whereFilter(Filter.andFilter([
    Filter.whereField("state", isEqualTo: "CA"),
    Filter.orFilter([
        Filter.whereField("capital", isEqualTo: true),
        Filter.whereField("population", isGreaterThanOrEqualTo: 1000000);
    ])
]))
Objective-C
Note: This product is not available on watchOS and App Clip targets.
FIRCollectionReference *collection = [self.db collectionWithPath:@"cities"];
FIRQuery *query = [collection queryWhereFilter:[FIRFilter andFilterWithFilters:@[
  [FIRFilter filterWhereField:@"state" isEqualTo:@"CA"],
  [FIRFilter orFilterWithFilters:@[
    [FIRFilter filterWhereField:@"capital" isEqualTo:@YES],
    [FIRFilter filterWhereField:@"population" isGreaterThanOrEqualTo:@1000000]
  ]]
]]];
Kotlin
Android
val query = collection.where(Filter.and(
    Filter.equalTo("state", "CA"),
    Filter.or(
        Filter.equalTo("capital", true),
        Filter.greaterThanOrEqualTo("population", 1000000)
    )
))
Java
Android
Query query = collection.where(Filter.and(
    Filter.equalTo("state", "CA"),
    Filter.or(
        Filter.equalTo("capital", true),
        Filter.greaterThanOrEqualTo("population", 1000000)
    )
));

Dart

var query = db.collection("cities").where(
      Filter.and(
        Filter("state", isEqualTo: "CA"),
        Filter.or(
          Filter("capital", isEqualTo: true),
          Filter("population", isGreaterThan: 1000000),
        ),
      ),
    );
Java

Snippet not available.

Python

Snippet not available.

Python
(Async)

Snippet not available.

C++

Snippet not available.

Node.js
const bigCitiesInCalifornia = await citiesRef
  .where('state', '==', 'CA')
  .where(
    Filter.or(
      Filter.where('capital', '==', true),
      Filter.where('population', '>=', 1000000)
    )
  )
  .get();
Go

Snippet not available.

PHP

Snippet not available.

Unity
Query query = citiesRef.Where(Filter.And(
    Filter.EqualTo("state", "CA"),
    Filter.Or(
        Filter.EqualTo("capital", true),
        Filter.GreaterThanOrEqualTo("population", 1000000)
    )
));
C#

Snippet not available.

Ruby

Snippet not available.

Limitations

Note the following limitations for or queries:

For a full description of limitations, see Query limitations.

Collection group queries

A collection group consists of all collections with the same ID. By default, queries retrieve results from a single collection in your database. Use a collection group query to retrieve documents from a collection group instead of from a single collection.

For example, you can create a landmarks collection group by adding a landmarks subcollection to each city:

Web version 9

import { collection, addDoc } from "firebase/firestore";  

const citiesRef = collection(db, 'cities');

await Promise.all([
    addDoc(collection(citiesRef, 'SF', 'landmarks'), {
        name: 'Golden Gate Bridge',
        type: 'bridge'
    }),
    addDoc(collection(citiesRef, 'SF', 'landmarks'), {
        name: 'Legion of Honor',
        type: 'museum'
    }),
    addDoc(collection(citiesRef, 'LA', 'landmarks'), {
        name: 'Griffith Park',
        type: 'park'
    }),
    addDoc(collection(citiesRef, 'LA', 'landmarks'), {
        name: 'The Getty',
        type: 'museum'
    }),
    addDoc(collection(citiesRef, 'DC', 'landmarks'), {
        name: 'Lincoln Memorial',
        type: 'memorial'
    }),
    addDoc(collection(citiesRef, 'DC', 'landmarks'), {
        name: 'National Air and Space Museum',
        type: 'museum'
    }),
    addDoc(collection(citiesRef, 'TOK', 'landmarks'), {
        name: 'Ueno Park',
        type: 'park'
    }),
    addDoc(collection(citiesRef, 'TOK', 'landmarks'), {
        name: 'National Museum of Nature and Science',
        type: 'museum'
    }),
    addDoc(collection(citiesRef, 'BJ', 'landmarks'), {
        name: 'Jingshan Park',
        type: 'park'
    }),
    addDoc(collection(citiesRef, 'BJ', 'landmarks'), {
        name: 'Beijing Ancient Observatory',
        type: 'museum'
    })
]);

Web version 8

var citiesRef = db.collection('cities');

var landmarks = Promise.all([
    citiesRef.doc('SF').collection('landmarks').doc().set({
        name: 'Golden Gate Bridge',
        type: 'bridge'
    }),
    citiesRef.doc('SF').collection('landmarks').doc().set({
        name: 'Legion of Honor',
        type: 'museum'
    }),
    citiesRef.doc('LA').collection('landmarks').doc().set({
        name: 'Griffith Park',
        type: 'park'
    }),
    citiesRef.doc('LA').collection('landmarks').doc().set({
        name: 'The Getty',
        type: 'museum'
    }),
    citiesRef.doc('DC').collection('landmarks').doc().set({
        name: 'Lincoln Memorial',
        type: 'memorial'
    }),
    citiesRef.doc('DC').collection('landmarks').doc().set({
        name: 'National Air and Space Museum',
        type: 'museum'
    }),
    citiesRef.doc('TOK').collection('landmarks').doc().set({
        name: 'Ueno Park',
        type: 'park'
    }),
    citiesRef.doc('TOK').collection('landmarks').doc().set({
        name: 'National Museum of Nature and Science',
        type: 'museum'
    }),
    citiesRef.doc('BJ').collection('landmarks').doc().set({
        name: 'Jingshan Park',
        type: 'park'
    }),
    citiesRef.doc('BJ').collection('landmarks').doc().set({
        name: 'Beijing Ancient Observatory',
        type: 'museum'
    })
]);
Swift
Note: This product is not available on watchOS and App Clip targets.
let citiesRef = db.collection("cities")

var data = ["name": "Golden Gate Bridge", "type": "bridge"]
citiesRef.document("SF").collection("landmarks").addDocument(data: data)

data = ["name": "Legion of Honor", "type": "museum"]
citiesRef.document("SF").collection("landmarks").addDocument(data: data)

data = ["name": "Griffith Park", "type": "park"]
citiesRef.document("LA").collection("landmarks").addDocument(data: data)

data = ["name": "The Getty", "type": "museum"]
citiesRef.document("LA").collection("landmarks").addDocument(data: data)

data = ["name": "Lincoln Memorial", "type": "memorial"]
citiesRef.document("DC").collection("landmarks").addDocument(data: data)

data = ["name": "National Air and Space Museum", "type": "museum"]
citiesRef.document("DC").collection("landmarks").addDocument(data: data)

data = ["name": "Ueno Park", "type": "park"]
citiesRef.document("TOK").collection("landmarks").addDocument(data: data)

data = ["name": "National Museum of Nature and Science", "type": "museum"]
citiesRef.document("TOK").collection("landmarks").addDocument(data: data)

data = ["name": "Jingshan Park", "type": "park"]
citiesRef.document("BJ").collection("landmarks").addDocument(data: data)

data = ["name": "Beijing Ancient Observatory", "type": "museum"]
citiesRef.document("BJ").collection("landmarks").addDocument(data: data)
Objective-C
Note: This product is not available on watchOS and App Clip targets.
FIRCollectionReference *citiesRef = [self.db collectionWithPath:@"cities"];

NSDictionary *data = @{@"name": @"Golden Gate Bridge", @"type": @"bridge"};
[[[citiesRef documentWithPath:@"SF"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Legion of Honor", @"type": @"museum"};
[[[citiesRef documentWithPath:@"SF"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Griffith Park", @"type": @"park"};
[[[citiesRef documentWithPath:@"LA"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"The Getty", @"type": @"museum"};
[[[citiesRef documentWithPath:@"LA"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Lincoln Memorial", @"type": @"memorial"};
[[[citiesRef documentWithPath:@"DC"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"National Air and Space Museum", @"type": @"museum"};
[[[citiesRef documentWithPath:@"DC"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Ueno Park", @"type": @"park"};
[[[citiesRef documentWithPath:@"TOK"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"National Museum of Nature and Science", @"type": @"museum"};
[[[citiesRef documentWithPath:@"TOK"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Jingshan Park", @"type": @"park"};
[[[citiesRef documentWithPath:@"BJ"] collectionWithPath:@"landmarks"] addDocumentWithData:data];

data = @{@"name": @"Beijing Ancient Observatory", @"type": @"museum"};
[[[citiesRef documentWithPath:@"BJ"] collectionWithPath:@"landmarks"] addDocumentWithData:data];
Kotlin
Android
val citiesRef = db.collection("cities")

val ggbData = mapOf(
    "name" to "Golden Gate Bridge",
    "type" to "bridge",
)
citiesRef.document("SF").collection("landmarks").add(ggbData)

val lohData = mapOf(
    "name" to "Legion of Honor",
    "type" to "museum",
)
citiesRef.document("SF").collection("landmarks").add(lohData)

val gpData = mapOf(
    "name" to "Griffth Park",
    "type" to "park",
)
citiesRef.document("LA").collection("landmarks").add(gpData)

val tgData = mapOf(
    "name" to "The Getty",
    "type" to "museum",
)
citiesRef.document("LA").collection("landmarks").add(tgData)

val lmData = mapOf(
    "name" to "Lincoln Memorial",
    "type" to "memorial",
)
citiesRef.document("DC").collection("landmarks").add(lmData)

val nasaData = mapOf(
    "name" to "National Air and Space Museum",
    "type" to "museum",
)
citiesRef.document("DC").collection("landmarks").add(nasaData)

val upData = mapOf(
    "name" to "Ueno Park",
    "type" to "park",
)
citiesRef.document("TOK").collection("landmarks").add(upData)

val nmData = mapOf(
    "name" to "National Musuem of Nature and Science",
    "type" to "museum",
)
citiesRef.document("TOK").collection("landmarks").add(nmData)

val jpData = mapOf(
    "name" to "Jingshan Park",
    "type" to "park",
)
citiesRef.document("BJ").collection("landmarks").add(jpData)

val baoData = mapOf(
    "name" to "Beijing Ancient Observatory",
    "type" to "musuem",
)
citiesRef.document("BJ").collection("landmarks").add(baoData)
Java
Android
CollectionReference citiesRef = db.collection("cities");

Map<String, Object> ggbData = new HashMap<>();
ggbData.put("name", "Golden Gate Bridge");
ggbData.put("type", "bridge");
citiesRef.document("SF").collection("landmarks").add(ggbData);

Map<String, Object> lohData = new HashMap<>();
lohData.put("name", "Legion of Honor");
lohData.put("type", "museum");
citiesRef.document("SF").collection("landmarks").add(lohData);

Map<String, Object> gpData = new HashMap<>();
gpData.put("name", "Griffith Park");
gpData.put("type", "park");
citiesRef.document("LA").collection("landmarks").add(gpData);

Map<String, Object> tgData = new HashMap<>();
tgData.put("name", "The Getty");
tgData.put("type", "museum");
citiesRef.document("LA").collection("landmarks").add(tgData);

Map<String, Object> lmData = new HashMap<>();
lmData.put("name", "Lincoln Memorial");
lmData.put("type", "memorial");
citiesRef.document("DC").collection("landmarks").add(lmData);

Map<String, Object> nasaData = new HashMap<>();
nasaData.put("name", "National Air and Space Museum");
nasaData.put("type", "museum");
citiesRef.document("DC").collection("landmarks").add(nasaData);

Map<String, Object> upData = new HashMap<>();
upData.put("name", "Ueno Park");
upData.put("type", "park");
citiesRef.document("TOK").collection("landmarks").add(upData);

Map<String, Object> nmData = new HashMap<>();
nmData.put("name", "National Museum of Nature and Science");
nmData.put("type", "museum");
citiesRef.document("TOK").collection("landmarks").add(nmData);

Map<String, Object> jpData = new HashMap<>();
jpData.put("name", "Jingshan Park");
jpData.put("type", "park");
citiesRef.document("BJ").collection("landmarks").add(jpData);

Map<String, Object> baoData = new HashMap<>();
baoData.put("name", "Beijing Ancient Observatory");
baoData.put("type", "museum");
citiesRef.document("BJ").collection("landmarks").add(baoData);

Dart

final citiesRef = db.collection("cities");

final ggbData = {"name": "Golden Gate Bridge", "type": "bridge"};
citiesRef.doc("SF").collection("landmarks").add(ggbData);

final lohData = {"name": "Legion of Honor", "type": "museum"};
citiesRef.doc("SF").collection("landmarks").add(lohData);

final gpData = {"name": "Griffth Park", "type": "park"};
citiesRef.doc("LA").collection("landmarks").add(gpData);

final tgData = {"name": "The Getty", "type": "museum"};
citiesRef.doc("LA").collection("landmarks").add(tgData);

final lmData = {"name": "Lincoln Memorial", "type": "memorial"};
citiesRef.doc("DC").collection("landmarks").add(lmData);

final nasaData = {
  "name": "National Air and Space Museum",
  "type": "museum"
};
citiesRef.doc("DC").collection("landmarks").add(nasaData);

final upData = {"name": "Ueno Park", "type": "park"};
citiesRef.doc("TOK").collection("landmarks").add(upData);

final nmData = {
  "name": "National Musuem of Nature and Science",
  "type": "museum"
};
citiesRef.doc("TOK").collection("landmarks").add(nmData);

final jpData = {"name": "Jingshan Park", "type": "park"};
citiesRef.doc("BJ").collection("landmarks").add(jpData);

final baoData = {"name": "Beijing Ancient Observatory", "type": "musuem"};
citiesRef.doc("BJ").collection("landmarks").add(baoData);
Java
CollectionReference cities = db.collection("cities");

final List<ApiFuture<WriteResult>> futures =
    Arrays.asList(
        cities
            .document("SF")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "Golden Gate Bridge");
                    put("type", "bridge");
                  }
                }),
        cities
            .document("SF")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "Legion of Honor");
                    put("type", "museum");
                  }
                }),
        cities
            .document("LA")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "Griffith Park");
                    put("type", "park");
                  }
                }),
        cities
            .document("LA")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "The Getty");
                    put("type", "museum");
                  }
                }),
        cities
            .document("DC")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "Lincoln Memorial");
                    put("type", "memorial");
                  }
                }),
        cities
            .document("DC")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "National Air and Space Museum");
                    put("type", "museum");
                  }
                }),
        cities
            .document("TOK")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "Ueno Park");
                    put("type", "park");
                  }
                }),
        cities
            .document("TOK")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "National Museum of Nature and Science");
                    put("type", "museum");
                  }
                }),
        cities
            .document("BJ")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "Jingshan Park");
                    put("type", "park");
                  }
                }),
        cities
            .document("BJ")
            .collection("landmarks")
            .document()
            .set(
                new HashMap<String, String>() {
                  {
                    put("name", "Beijing Ancient Observatory");
                    put("type", "museum");
                  }
                }));
final List<WriteResult> landmarks = ApiFutures.allAsList(futures).get();
Python
cities = db.collection("cities")

sf_landmarks = cities.document("SF").collection("landmarks")
sf_landmarks.document().set({"name": "Golden Gate Bridge", "type": "bridge"})
sf_landmarks.document().set({"name": "Legion of Honor", "type": "museum"})
la_landmarks = cities.document("LA").collection("landmarks")
la_landmarks.document().set({"name": "Griffith Park", "type": "park"})
la_landmarks.document().set({"name": "The Getty", "type": "museum"})
dc_landmarks = cities.document("DC").collection("landmarks")
dc_landmarks.document().set({"name": "Lincoln Memorial", "type": "memorial"})
dc_landmarks.document().set(
    {"name": "National Air and Space Museum", "type": "museum"}
)
tok_landmarks = cities.document("TOK").collection("landmarks")
tok_landmarks.document().set({"name": "Ueno Park", "type": "park"})
tok_landmarks.document().set(
    {"name": "National Museum of Nature and Science", "type": "museum"}
)
bj_landmarks = cities.document("BJ").collection("landmarks")
bj_landmarks.document().set({"name": "Jingshan Park", "type": "park"})
bj_landmarks.document().set(
    {"name": "Beijing Ancient Observatory", "type": "museum"}
)
Python
(Async)
cities = db.collection("cities")

sf_landmarks = cities.document("SF").collection("landmarks")
await sf_landmarks.document().set({"name": "Golden Gate Bridge", "type": "bridge"})
await sf_landmarks.document().set({"name": "Legion of Honor", "type": "museum"})
la_landmarks = cities.document("LA").collection("landmarks")
await la_landmarks.document().set({"name": "Griffith Park", "type": "park"})
await la_landmarks.document().set({"name": "The Getty", "type": "museum"})
dc_landmarks = cities.document("DC").collection("landmarks")
await dc_landmarks.document().set({"name": "Lincoln Memorial", "type": "memorial"})
await dc_landmarks.document().set(
    {"name": "National Air and Space Museum", "type": "museum"}
)
tok_landmarks = cities.document("TOK").collection("landmarks")
await tok_landmarks.document().set({"name": "Ueno Park", "type": "park"})
await tok_landmarks.document().set(
    {"name": "National Museum of Nature and Science", "type": "museum"}
)
bj_landmarks = cities.document("BJ").collection("landmarks")
await bj_landmarks.document().set({"name": "Jingshan Park", "type": "park"})
await bj_landmarks.document().set(
    {"name": "Beijing Ancient Observatory", "type": "museum"}
)
C++
// Get a new write batch
WriteBatch batch = db->batch();

DocumentReference sf_ref = db->Collection("cities").Document("SF");
batch.Set(sf_ref,{{"name", FieldValue::String("Golden Gate Bridge")}, {"type", FieldValue::String("bridge")}});
batch.Set(sf_ref,{{"name", FieldValue::String("Legion of Honor")}, {"type", FieldValue::String("museum")}});

DocumentReference la_ref = db->Collection("cities").Document("LA");
batch.Set(la_ref,{{"name", FieldValue::String("Griffith Park")}, {"type", FieldValue::String("park")}});
batch.Set(la_ref,{{"name", FieldValue::String("The Getty")}, {"type", FieldValue::String("museum")}});

DocumentReference dc_ref = db->Collection("cities").Document("DC");
batch.Set(dc_ref,{{"name", FieldValue::String("Lincoln Memorial")}, {"type", FieldValue::String("memorial")}});
batch.Set(dc_ref,{{"name", FieldValue::String("National Air and Space Museum")}, {"type", FieldValue::String("museum")}});

DocumentReference tok_ref = db->Collection("cities").Document("TOK");
batch.Set(tok_ref,{{"name", FieldValue::String("Ueno Park")}, {"type", FieldValue::String("park")}});
batch.Set(tok_ref,{{"name", FieldValue::String("National Museum of Nature and Science")}, {"type", FieldValue::String("museum")}});

DocumentReference bj_ref = db->Collection("cities").Document("BJ");
batch.Set(bj_ref,{{"name", FieldValue::String("Jingshan Park")}, {"type", FieldValue::String("park")}});
batch.Set(bj_ref,{{"name", FieldValue::String("Beijing Ancient Observatory")}, {"type", FieldValue::String("museum")}});

// Commit the batch
batch.Commit().OnCompletion([](const Future<void>& future) {
  if (future.error() == Error::kErrorOk) {
    std::cout << "Write batch success!" << std::endl;
  } else {
    std::cout << "Write batch failure: " << future.error_message() << std::endl;
  }
});
Node.js
const citiesRef = db.collection('cities');

await citiesRef.doc('SF').collection('landmarks').doc().set({
  name: 'Golden Gate Bridge',
  type: 'bridge'
});
await citiesRef.doc('SF').collection('landmarks').doc().set({
  name: 'Legion of Honor',
  type: 'museum'
});
await citiesRef.doc('LA').collection('landmarks').doc().set({
  name: 'Griffith Park',
  type: 'park'
});
await citiesRef.doc('LA').collection('landmarks').doc().set({
  name: 'The Getty',
  type: 'museum'
});
await citiesRef.doc('DC').collection('landmarks').doc().set({
  name: 'Lincoln Memorial',
  type: 'memorial'
});
await citiesRef.doc('DC').collection('landmarks').doc().set({
  name: 'National Air and Space Museum',
  type: 'museum'
});
await citiesRef.doc('TOK').collection('landmarks').doc().set({
  name: 'Ueno Park',
  type: 'park'
});
await citiesRef.doc('TOK').collection('landmarks').doc().set({
  name: 'National Museum of Nature and Science',
  type: 'museum'
});
await citiesRef.doc('BJ').collection('landmarks').doc().set({
  name: 'Jingshan Park',
  type: 'park'
});
await citiesRef.doc('BJ').collection('landmarks').doc().set({ 
  name: 'Beijing Ancient Observatory',
  type: 'museum'
});
Go
import (
	"context"
	"fmt"

	"cloud.google.com/go/firestore"
)

// collectionGroupSetup sets up a collection group to query.
func collectionGroupSetup(projectID, cityCollection string) error {
	ctx := context.Background()

	client, err := firestore.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("firestore.NewClient: %w", err)
	}
	defer client.Close()

	landmarks := []struct {
		city, name, t string
	}{
		{"SF", "Golden Gate Bridge", "bridge"},
		{"SF", "Legion of Honor", "museum"},
		{"LA", "Griffith Park", "park"},
		{"LA", "The Getty", "museum"},
		{"DC", "Lincoln Memorial", "memorial"},
		{"DC", "National Air and Space Museum", "museum"},
		{"TOK", "Ueno Park", "park"},
		{"TOK", "National Museum of Nature and Science", "museum"},
		{"BJ", "Jingshan Park", "park"},
		{"BJ", "Beijing Ancient Observatory", "museum"},
	}

	cities := client.Collection(cityCollection)
	for _, l := range landmarks {
		if _, err := cities.Doc(l.city).Collection("landmarks").NewDoc().Set(ctx, map[string]string{
			"name": l.name,
			"type": l.t,
		}); err != nil {
			return fmt.Errorf("Set: %w", err)
		}
	}

	return nil
}
PHP
$citiesRef = $db->collection('samples/php/cities');
$citiesRef->document('SF')->collection('landmarks')->newDocument()->set([
    'name' => 'Golden Gate Bridge',
    'type' => 'bridge'
]);
$citiesRef->document('SF')->collection('landmarks')->newDocument()->set([
    'name' => 'Legion of Honor',
    'type' => 'museum'
]);
$citiesRef->document('LA')->collection('landmarks')->newDocument()->set([
    'name' => 'Griffith Park',
    'type' => 'park'
]);
$citiesRef->document('LA')->collection('landmarks')->newDocument()->set([
    'name' => 'The Getty',
    'type' => 'museum'
]);
$citiesRef->document('DC')->collection('landmarks')->newDocument()->set([
    'name' => 'Lincoln Memorial',
    'type' => 'memorial'
]);
$citiesRef->document('DC')->collection('landmarks')->newDocument()->set([
    'name' => 'National Air and Space Museum',
    'type' => 'museum'
]);
$citiesRef->document('TOK')->collection('landmarks')->newDocument()->set([
    'name' => 'Ueno Park',
    'type' => 'park'
]);
$citiesRef->document('TOK')->collection('landmarks')->newDocument()->set([
    'name' => 'National Museum of Nature and Science',
    'type' => 'museum'
]);
$citiesRef->document('BJ')->collection('landmarks')->newDocument()->set([
    'name' => 'Jingshan Park',
    'type' => 'park'
]);
$citiesRef->document('BJ')->collection('landmarks')->newDocument()->set([
    'name' => 'Beijing Ancient Observatory',
    'type' => 'museum'
]);
print('Added example landmarks collections to the cities collection.' . PHP_EOL);
Unity
List<Task<DocumentReference>> futures =
    new List<Task<DocumentReference>>(){
        citiesRef
            .Document("SF")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>()
                {
                    {"name", "Golden Gate Bridge"},
                    {"type", "bridge"},
                }
                ),
        citiesRef
            .Document("SF")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>()
                {
                    {"name", "Legion of Honor"},
                    {"type", "museum"},
                }
                ),
        citiesRef
            .Document("LA")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>() 
                {
                    {"name", "Griffith Park"},
                    {"type", "park"},
                }
                ),
        citiesRef
            .Document("LA")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>() 
                {
                    {"name", "The Getty"},
                    {"type", "museum"},
                }
                ),
        citiesRef
            .Document("DC")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>() 
                {
                    {"name", "Lincoln Memorial"},
                    {"type", "memorial"},
                }
                ),
        citiesRef
            .Document("DC")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>()
                {
                    {"name", "National Air and Space Museum"},
                    {"type", "museum"},
                }
                ),
        citiesRef
            .Document("TOK")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>()
                {
                    {"name", "Ueno Park"},
                    {"type", "park"},
                }
                ),
        citiesRef
            .Document("TOK")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>()
                {
                    {"name", "National Museum of Nature and Science"},
                    {"type", "museum"},
                }
                ),
        citiesRef
            .Document("BJ")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>()
                {
                    {"name", "Jingshan Park"},
                    {"type", "park"},
                }
                ),
        citiesRef
            .Document("BJ")
            .Collection("landmarks")
            .AddAsync(
                new Dictionary<string, object>()
                {
                    {"name", "Beijing Ancient Observatory"},
                    {"type", "museum"},
                }
                )};
DocumentReference[] landmarks = Task.WhenAll(futures).Result;
C#
// Copyright(c) 2017 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

using Google.Cloud.Firestore;
using Google.Cloud.Firestore.Admin.V1;
using Google.Protobuf.WellKnownTypes;
using Grpc.Core;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading.Tasks;
using static Google.Cloud.Firestore.Admin.V1.Index.Types;

namespace GoogleCloudSamples
{
    public class QueryData
    {
        public static string Usage = @"Usage:
C:\> dotnet run command YOUR_PROJECT_ID

Where command is one of
    query-create-examples
    create-query-state
    create-query-capital
    simple-queries
    array-contains-query
    array-contains-any-query
    in-query
    in-query-array
    collection-group-query
    subcollection-query
    chained-query
    composite-index-chained-query
    range-query
    invalid-range-query
    multiple-inequalities
";
        private static async Task QueryCreateExamples(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            // Note: the extra braces here are just to allow multiple citiesRef local variables.
            {
                CollectionReference citiesRef = db.Collection("cities");
                await citiesRef.Document("SF").SetAsync(new Dictionary<string, object>
                {
                    { "Name", "San Francisco" },
                    { "State", "CA" },
                    { "Country", "USA" },
                    { "Capital", false },
                    { "Population", 860000 },
                    { "Density", 18000 },
                    { "Regions", new[] {"west_coast", "norcal"} }
                });
                await citiesRef.Document("LA").SetAsync(new Dictionary<string, object>
                {
                    { "Name", "Los Angeles" },
                    { "State", "CA" },
                    { "Country", "USA" },
                    { "Capital", false },
                    { "Population", 3900000 },
                    { "Density", 8300 },
                    { "Regions", new[] {"west_coast", "socal"} }
                });
                await citiesRef.Document("DC").SetAsync(new Dictionary<string, object>
                {
                    { "Name", "Washington D.C." },
                    { "State", null },
                    { "Country", "USA" },
                    { "Capital", true },
                    { "Population", 680000 },
                    { "Density", 11300 },
                    { "Regions", new[] {"east_coast"} }
                });
                await citiesRef.Document("TOK").SetAsync(new Dictionary<string, object>
                {
                    { "Name", "Tokyo" },
                    { "State", null },
                    { "Country", "Japan" },
                    { "Capital", true },
                    { "Population", 9000000 },
                    { "Density", 16000 },
                    { "Regions", new[] {"kanto", "honshu"} }
                });
                await citiesRef.Document("BJ").SetAsync(new Dictionary<string, object>
                {
                    { "Name", "Beijing" },
                    { "State", null },
                    { "Country", "China" },
                    { "Capital", true },
                    { "Population", 21500000 },
                    { "Density", 3500 },
                    { "Regions", new[] {"jingjinji", "hebei"} }
                });
                Console.WriteLine("Added example cities data to the cities collection.");
            }

            {
                CollectionReference citiesRef = db.Collection("cities");
                await citiesRef.Document("SF").Collection("landmarks").Document()
                    .SetAsync(new { Name = "Golden Gate Bridge", Type = "bridge" });
                await citiesRef.Document("SF").Collection("landmarks").Document()
                    .SetAsync(new { Name = "Legion of Honor", Type = "museum" });
                await citiesRef.Document("LA").Collection("landmarks").Document()
                    .SetAsync(new { Name = "Griffith Park", Type = "park" });
                await citiesRef.Document("DC").Collection("landmarks").Document()
                    .SetAsync(new { Name = "Lincoln Memorial", Type = "memorial" });
                await citiesRef.Document("DC").Collection("landmarks").Document()
                    .SetAsync(new { Name = "National Air And Space Museum", Type = "museum" });
                await citiesRef.Document("TOK").Collection("landmarks").Document()
                    .SetAsync(new { Name = "Ueno Park", Type = "park" });
                await citiesRef.Document("TOK").Collection("landmarks").Document()
                    .SetAsync(new { Name = "National Museum of Nature and Science", Type = "museum" });
                await citiesRef.Document("BJ").Collection("landmarks").Document()
                    .SetAsync(new { Name = "Jingshan Park", Type = "park" });
                await citiesRef.Document("BJ").Collection("landmarks").Document()
                    .SetAsync(new { Name = "Beijing Ancient Observatory", Type = "museum" });
            }
        }

        private static async Task CreateQueryState(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query query = citiesRef.WhereEqualTo("State", "CA");
            QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query State=CA", documentSnapshot.Id);
            }
        }

        private static async Task CreateQueryCapital(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query query = citiesRef.WhereEqualTo("Capital", true);
            QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query Capital=true", documentSnapshot.Id);
            }
        }

        private static async Task SimpleQueries(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query stateQuery = citiesRef.WhereEqualTo("State", "CA");
            Query populationQuery = citiesRef.WhereGreaterThan("Population", 1000000);
            Query nameQuery = citiesRef.WhereGreaterThanOrEqualTo("Name", "San Francisco");
            QuerySnapshot stateQuerySnapshot = await stateQuery.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in stateQuerySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query State=CA", documentSnapshot.Id);
            }
            QuerySnapshot populationQuerySnapshot = await populationQuery.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in populationQuerySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query Population>1000000", documentSnapshot.Id);
            }
            QuerySnapshot nameQuerySnapshot = await nameQuery.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in nameQuerySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query Name>=San Francisco", documentSnapshot.Id);
            }
        }

        private static async Task ArrayContainsQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query query = citiesRef.WhereArrayContains("Regions", "west_coast");
            QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query 'Regions array_contains west_coast'", documentSnapshot.Id);
            }
        }

        private static async Task ArrayContainsAnyQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query query = citiesRef.WhereArrayContainsAny("Regions", new[] { "west_coast", "east_coast" });
            QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query 'Regions array_contains_any {{west_coast, east_coast}}'", documentSnapshot.Id);
            }
        }

        private static async Task InQueryWithoutArray(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query query = citiesRef.WhereIn("Country", new[] { "USA", "Japan" });
            QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query 'Country in {{USA, Japan}}'", documentSnapshot.Id);
            }
        }

        private static async Task InQueryWithArray(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query query = citiesRef.WhereIn("Regions",
                new[] { new[] { "west_coast" }, new[] { "east_coast" } });
            QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query 'Regions in {{west_coast}}, {{east_coast}}'", documentSnapshot.Id);
            }
        }

        private static async Task CollectionGroupQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            Query museums = db.CollectionGroup("landmarks").WhereEqualTo("Type", "museum");
            QuerySnapshot querySnapshot = await museums.GetSnapshotAsync();
            foreach (DocumentSnapshot document in querySnapshot.Documents)
            {
                Console.WriteLine($"{document.Reference.Path}: {document.GetValue<string>("Name")}");
            }
        }

        private static async Task SubcollectionQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference landmarks = db.Collection("cities").Document("SF").Collection("landmarks");
            QuerySnapshot querySnapshot = await landmarks.GetSnapshotAsync();
            foreach (DocumentSnapshot document in querySnapshot.Documents)
            {
                Console.WriteLine($"{document.Reference.Path}: {document.GetValue<string>("Name")}");
            }
        }

        private static async Task ChainedQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query chainedQuery = citiesRef
                .WhereEqualTo("State", "CA")
                .WhereEqualTo("Name", "San Francisco");
            QuerySnapshot querySnapshot = await chainedQuery.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query State=CA and Name=San Francisco", documentSnapshot.Id);
            }
        }

        private static async Task CompositeIndexChainedQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query chainedQuery = citiesRef
                .WhereEqualTo("State", "CA")
                .WhereLessThan("Population", 1000000);
            QuerySnapshot querySnapshot = await chainedQuery.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query State=CA and Population<1000000", documentSnapshot.Id);
            }
        }

        private static async Task RangeQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query rangeQuery = citiesRef
                .WhereGreaterThanOrEqualTo("State", "CA")
                .WhereLessThanOrEqualTo("State", "IN");
            QuerySnapshot querySnapshot = await rangeQuery.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot.Documents)
            {
                Console.WriteLine("Document {0} returned by query CA<=State<=IN", documentSnapshot.Id);
            }
        }

        private static void InvalidRangeQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            CollectionReference citiesRef = db.Collection("cities");
            Query invalidRangeQuery = citiesRef
                .WhereGreaterThanOrEqualTo("State", "CA")
                .WhereGreaterThan("Population", 1000000);
        }

        private static async Task MultipleInequalitiesQuery(string project)
        {
            FirestoreDb db = FirestoreDb.Create(project);
            FirestoreAdminClient adminClient = FirestoreAdminClient.Create();
            var index = new Google.Cloud.Firestore.Admin.V1.Index
            {
                Fields =
                {
                    new IndexField { FieldPath = "Density", Order = IndexField.Types.Order.Ascending },
                    new IndexField { FieldPath = "Population", Order = IndexField.Types.Order.Ascending }
                },
                QueryScope = QueryScope.Collection
            };

            // We speculatively try to create the index, and just ignore an error of it already existing.
            try
            {
                var lro = await adminClient.CreateIndexAsync(new CollectionGroupName(db.ProjectId, db.DatabaseId, "cities"), index);
                await lro.PollUntilCompletedAsync();
            }
            catch (RpcException ex) when (ex.StatusCode == StatusCode.AlreadyExists)
            {
                // Assume the index is okay.
            }

            CollectionReference citiesRef = db.Collection("cities");
            Query query = citiesRef
                .WhereGreaterThan("Population", 1000000)
                .WhereLessThan("Density", 10000);
            QuerySnapshot querySnapshot = await query.GetSnapshotAsync();
            foreach (DocumentSnapshot documentSnapshot in querySnapshot)
            {
                var name = documentSnapshot.GetValue<string>("Name");
                var population = documentSnapshot.GetValue<int>("Population");
                var density = documentSnapshot.GetValue<int>("Density");
                Console.WriteLine($"City '{name}' returned by query. Population={population}; Density={density}");
            }
        }

        public static void Main(string[] args)
        {
            if (args.Length < 2)
            {
                Console.Write(Usage);
                return;
            }
            string command = args[0].ToLower();
            string project = string.Join(" ",
                new ArraySegment<string>(args, 1, args.Length - 1));
            switch (command)
            {
                case "query-create-examples":
                    QueryCreateExamples(project).Wait();
                    break;

                case "create-query-state":
                    CreateQueryState(project).Wait();
                    break;

                case "create-query-capital":
                    CreateQueryCapital(project).Wait();
                    break;

                case "simple-queries":
                    SimpleQueries(project).Wait();
                    break;

                case "array-contains-query":
                    ArrayContainsQuery(project).Wait();
                    break;

                case "array-contains-any-query":
                    ArrayContainsAnyQuery(project).Wait();
                    break;

                case "in-query":
                    InQueryWithoutArray(project).Wait();
                    break;

                case "in-query-array":
                    InQueryWithArray(project).Wait();
                    break;

                case "collection-group-query":
                    CollectionGroupQuery(project).Wait();
                    break;

                case "subcollection-query":
                    SubcollectionQuery(project).Wait();
                    break;

                case "chained-query":
                    ChainedQuery(project).Wait();
                    break;

                case "composite-index-chained-query":
                    CompositeIndexChainedQuery(project).Wait();
                    break;

                case "range-query":
                    RangeQuery(project).Wait();
                    break;

                case "invalid-range-query":
                    InvalidRangeQuery(project);
                    break;

                case "multiple-inequalities":
                    MultipleInequalitiesQuery(project).Wait();
                    break;

                default:
                    Console.Write(Usage);
                    return;
            }
        }
    }
}
Ruby
cities_ref = firestore.col collection_path

sf_landmarks = cities_ref.document("SF").collection("landmarks")
sf_landmarks.document.set(
  {
    name: "Golden Gate Bridge",
    type: "bridge"
  }
)
sf_landmarks.document.set(
  {
    name: "Legion of Honor",
    type: "museum"
  }
)

la_landmarks = cities_ref.document("LA").collection("landmarks")
la_landmarks.document.set(
  {
    name: "Griffith Park",
    type: "park"
  }
)
la_landmarks.document.set(
  {
    name: "The Getty",
    type: "museum"
  }
)

dc_landmarks = cities_ref.document("DC").collection("landmarks")
dc_landmarks.document.set(
  {
    name: "Lincoln Memorial",
    type: "memorial"
  }
)
dc_landmarks.document.set(
  {
    name: "National Air and Space Museum",
    type: "museum"
  }
)

tok_landmarks = cities_ref.document("TOK").collection("landmarks")
tok_landmarks.document.set(
  {
    name: "Ueno Park",
    type: "park"
  }
)
tok_landmarks.document.set(
  {
    name: "National Museum of Nature and Science",
    type: "museum"
  }
)

bj_landmarks = cities_ref.document("BJ").collection("landmarks")
bj_landmarks.document.set(
  {
    name: "Jingshan Park",
    type: "park"
  }
)
bj_landmarks.document.set(
  {
    name: "Beijing Ancient Observatory",
    type: "museum"
  }
)

We can use the simple and compound query described earlier to query a single city's landmarks subcollection, but you might also want to retrieve results from every city's landmarks subcollection at once.

The landmarks collection group consists of all collections with the ID landmarks, and you can query it using a collection group query. For example, this collection group query retrieves all museum landmarks across all cities:

Web version 9

import { collectionGroup, query, where, getDocs } from "firebase/firestore";  

const museums = query(collectionGroup(db, 'landmarks'), where('type', '==', 'museum'));
const querySnapshot = await getDocs(museums);
querySnapshot.forEach((doc) => {
    console.log(doc.id, ' => ', doc.data());
});

Web version 8

var museums = db.collectionGroup('landmarks').where('type', '==', 'museum');
museums.get().then((querySnapshot) => {
    querySnapshot.forEach((doc) => {
        console.log(doc.id, ' => ', doc.data());
    });
});
Swift
Note: This product is not available on watchOS and App Clip targets.
db.collectionGroup("landmarks").whereField("type", isEqualTo: "museum").getDocuments { (snapshot, error) in
  // ...
}
Objective-C
Note: This product is not available on watchOS and App Clip targets.
[[[self.db collectionGroupWithID:@"landmarks"] queryWhereField:@"type" isEqualTo:@"museum"]
    getDocumentsWithCompletion:^(FIRQuerySnapshot *snapshot, NSError *error) {
    // ...
}];
Kotlin
Android
db.collectionGroup("landmarks").whereEqualTo("type", "museum").get()
    .addOnSuccessListener { queryDocumentSnapshots ->
        // ...
    }
Java
Android
db.collectionGroup("landmarks").whereEqualTo("type", "museum").get()
        .addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
            @Override
            public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
                // ...
            }
        });

Dart

db
    .collectionGroup("landmarks")
    .where("type", isEqualTo: "museum")
    .get()
    .then(
      (res) => print("Successfully completed"),
      onError: (e) => print("Error completing: $e"),
    );
Java
final Query museums = db.collectionGroup("landmarks").whereEqualTo("type", "museum");
final ApiFuture<QuerySnapshot> querySnapshot = museums.get();
for (DocumentSnapshot document : querySnapshot.get().getDocuments()) {
  System.out.println(document.getId());
}
Python
museums = db.collection_group("landmarks").where(
    filter=FieldFilter("type", "==", "museum")
)
docs = museums.stream()
for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
Python
(Async)
museums = db.collection_group("landmarks").where(
    filter=FieldFilter("type", "==", "museum")
)
docs = museums.stream()
async for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
C++
db->CollectionGroup("landmarks")
.WhereEqualTo("type", FieldValue::String("museum")).Get()
.OnCompletion([](const firebase::Future<QuerySnapshot>& future) {
  if (future.error() == Error::kErrorOk) {
    for (const DocumentSnapshot& document : future.result()->documents()) {
      std::cout << document << std::endl;
    }
  } else {
    std::cout << "Error getting documents: " << future.error_message()
              << std::endl;
  }
});
Node.js
const querySnapshot = await db.collectionGroup('landmarks').where('type', '==', 'museum').get();
querySnapshot.forEach((doc) => {
  console.log(doc.id, ' => ', doc.data());
});
Go
import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/firestore"
	"google.golang.org/api/iterator"
)

// collectionGroupQuery runs a collection group query over the data created by
// collectionGroupSetup.
func collectionGroupQuery(w io.Writer, projectID string) error {
	ctx := context.Background()

	client, err := firestore.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("firestore.NewClient: %w", err)
	}
	defer client.Close()

	it := client.CollectionGroup("landmarks").Where("type", "==", "museum").Documents(ctx)
	for {
		doc, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return fmt.Errorf("documents iterator: %w", err)
		}
		fmt.Fprintf(w, "%s: %s", doc.Ref.ID, doc.Data()["name"])
	}

	return nil
}
PHP
$museums = $db->collectionGroup('landmarks')->where('type', '==', 'museum');
foreach ($museums->documents() as $document) {
    printf('%s => %s' . PHP_EOL, $document->id(), $document->data()['name']);
}
Unity
Query museums = db.CollectionGroup("landmarks").WhereEqualTo("type", "museum");
museums.GetSnapshotAsync().ContinueWithOnMainThread((querySnapshotTask) =>
{
    foreach (DocumentSnapshot documentSnapshot in querySnapshotTask.Result.Documents)
    {
        Debug.Log(String.Format("Document {0} returned by query State=CA", documentSnapshot.Id));
    } 
});
C#
Query museums = db.CollectionGroup("landmarks").WhereEqualTo("Type", "museum");
QuerySnapshot querySnapshot = await museums.GetSnapshotAsync();
foreach (DocumentSnapshot document in querySnapshot.Documents)
{
    Console.WriteLine($"{document.Reference.Path}: {document.GetValue<string>("Name")}");
}
Ruby
museums = firestore.collection_group("landmarks").where("type", "==", "museum")
museums.get do |museum|
  puts "#{museum[:type]} name is #{museum[:name]}."
end

Before using a collection group query, you must create an index that supports your collection group query. You can create an index through an error message, the console, or the Firebase CLI.

For the web and mobile SDKs, you must also create rules that allow your collection group queries.

Explain your query performance

Firestore allows you to measure performance of your queries on the backend and receive detailed performance statistics on backend query execution in return.

Query Explain results help you understand how your queries are executed, showing you inefficiencies and the location of likely server-side bottlenecks.

For more information, see the guide for Query Explain.

Query limitations

The following list summarizes Firestore query limitations:

  • Firestore provides support for logical OR queries through the or, in, and array-contains-any operators. These queries are limited to 30 disjunctions based on the query's disjunctive normal form.
  • You can use at most one array-contains clause per disjunction (or group). You can't combine array-contains with array-contains-any in the same disjunction.
  • You can't combine not-in with in, array-contains-any, or or in the same query.
  • Only a single not-in or != is allowed per query.
  • not-in supports up to 10 comparison values.
  • The sum of filters, sort orders, and parent document path (1 for a subcollection, 0 for a root collection) in a query cannot exceed 100. This is calculated based on the disjunctive normal form of the query.
  • A query with an inequality filter on a field implies ordering by that field and filters for existence of that field.

Limits on OR queries

To prevent a query from becoming too computationally expensive, Firestore limits how many AND and OR clauses you can combine. To apply this limit, Firestore converts queries that perform logical OR operations (or, in, and array-contains-any) to disjunctive normal form (also known as an OR of ANDs). Firestore limits a query to a maximum of 30 disjunctions in disjunctive normal form.

Disjunctive normal form

Firestore converts queries to disjunctive normal form by applying two rules:

  • Flatten

    Given conditions A, B, and C:

    A and (B and C) => A and B and C

  • Distributive Law

    Given conditions A, B, C, and D:

    • A and (B or C) => (A and B) or (A and C)
    • (A or B) and (C or D) => (A and C) or (A and D) or (B and C) or (B and D)

When applying these rules to in and array-contains-any queries, remember that these operators are shorthands for OR. For example, a in [1,2] is shorthand for a = 1 OR a = 2.

The following examples show the number of disjunctions for different queries:

QueryNumber of disjunctions
query(collectionRef, where("a", "==", 1))
      
1
query(collectionRef, or( where("a", "==", 1), where("b", "==", 2) ))
      
2
query(collectionRef,
        or( and( where("a", "==", 1), where("c", "==", 3) ),
            and( where("a", "==", 1), where("d", "==", 4) ),
            and( where("b", "==", 2), where("c", "==", 3) ),
            and( where("b", "==", 2), where("d", "==", 4) )
        )
      )
      
4
query(collectionRef,
        and( or( where("a", "==", 1), where("b", "==", 2) ),
             or( where("c", "==", 3), where("d", "==", 4) )
        )
      )
      

4

The disjunctive normal form of this query is equal to the query above.

query(collectionRef, where("a", "in", [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]) )
      
10
query(collectionRef,
        and( where("a", "in", [1, 2, 3, 4, 5]),
             where("b", "in", [1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
        )
      )
      

50

This query returns an error, because it surpasses the limit of 30 disjunctions.

query(collectionRef,
        or( where("a", "in", [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]),
            where("b", "in", [1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
        )
      )
      
20
query(collectionRef,
        and( where("a", "in", [1, 2, 3, 4, 5]),
             or( where("b", "==", 2),
                 where("c", "==", 3)
             )
        )
      )
      
10

orderBy and existence

When you order a query by a given field, the query can return only the documents where the order-by field exists.

For example, the following query would not return any documents where the population field is not set, even if they otherwise meet the query filters.

Java
db.collection("cities").whereEqualTo("country", USA).orderBy(population);

A related effect applies to inequalities. A query with an inequality filter on a field also implies ordering by that field. The following query does not return documents without a population field even if country = USA in that document . As a workaround, you can execute separate queries for each ordering or you can assign a value for all fields that you order by.

Java
db.collection(cities).where(or(country, USA), greaterThan(population, 250000));

The query above includes an implied order-by on the inequality and is equivalent to the following:

Java
db.collection(cities).where(or(country, USA), greaterThan(population, 250000)).orderBy(population);

What's next