FLOAT 매개변수를 사용하여 데이터를 쿼리합니다.
코드 샘플
C#
Spanner용 클라이언트 라이브러리를 설치하고 사용하는 방법은 Spanner 클라이언트 라이브러리를 참조하세요.
using Google.Cloud.Spanner.Data;
using System.Collections.Generic;
using System.Threading.Tasks;
public class QueryWithFloatAsyncSample
{
public class Venue
{
public int VenueId { get; set; }
public string VenueName { get; set; }
public float PopularityScore { get; set; }
}
public async Task<List<Venue>> QueryWithFloatAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
// Initialize a float variable to use for querying.
float exampleFloat = 0.8f;
using var connection = new SpannerConnection(connectionString);
var cmd = connection.CreateSelectCommand("SELECT VenueId, VenueName, PopularityScore FROM Venues WHERE PopularityScore > @ExampleFloat");
cmd.Parameters.Add("ExampleFloat", SpannerDbType.Float64, exampleFloat);
var venues = new List<Venue>();
using var reader = await cmd.ExecuteReaderAsync();
while (await reader.ReadAsync())
{
venues.Add(new Venue
{
VenueId = reader.GetFieldValue<int>("VenueId"),
VenueName = reader.GetFieldValue<string>("VenueName"),
PopularityScore = reader.GetFieldValue<float>("PopularityScore")
});
}
return venues;
}
}C++
Spanner용 클라이언트 라이브러리를 설치하고 사용하는 방법은 Spanner 클라이언트 라이브러리를 참조하세요.
void QueryWithFloatParameter(google::cloud::spanner::Client client) {
namespace spanner = ::google::cloud::spanner;
double example_float = 0.8;
spanner::SqlStatement select(
"SELECT VenueId, VenueName, PopularityScore FROM Venues"
" WHERE PopularityScore > @popularity_score",
{{"popularity_score", spanner::Value(example_float)}});
using RowType = std::tuple<std::int64_t, absl::optional<std::string>,
absl::optional<double>>;
auto rows = client.ExecuteQuery(std::move(select));
for (auto& row : spanner::StreamOf<RowType>(rows)) {
if (!row) throw std::move(row).status();
std::cout << "VenueId: " << std::get<0>(*row) << "\t";
std::cout << "VenueName: " << std::get<1>(*row).value() << "\t";
std::cout << "PopularityScore: " << std::get<2>(*row).value() << "\n";
}
std::cout << "Query completed for [spanner_query_with_float_parameter]\n";
}Go
Spanner용 클라이언트 라이브러리를 설치하고 사용하는 방법은 Spanner 클라이언트 라이브러리를 참조하세요.
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
"google.golang.org/api/iterator"
)
func queryWithFloat(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
var exampleFloat = 0.8
stmt := spanner.Statement{
SQL: `SELECT VenueId, VenueName, PopularityScore FROM Venues
WHERE PopularityScore > @popularityScore`,
Params: map[string]interface{}{
"popularityScore": exampleFloat,
},
}
iter := client.Single().Query(ctx, stmt)
defer iter.Stop()
for {
row, err := iter.Next()
if err == iterator.Done {
return nil
}
if err != nil {
return err
}
var venueID int64
var venueName string
var popularityScore float64
if err := row.Columns(&venueID, &venueName, &popularityScore); err != nil {
return err
}
fmt.Fprintf(w, "%d %s %f\n", venueID, venueName, popularityScore)
}
}
Java
Spanner용 클라이언트 라이브러리를 설치하고 사용하는 방법은 Spanner 클라이언트 라이브러리를 참조하세요.
static void queryWithFloat(DatabaseClient dbClient) {
float exampleFloat = 0.8f;
Statement statement =
Statement.newBuilder(
"SELECT VenueId, VenueName, PopularityScore FROM Venues "
+ "WHERE PopularityScore > @popularityScore")
.bind("popularityScore")
.to(exampleFloat)
.build();
try (ResultSet resultSet = dbClient.singleUse().executeQuery(statement)) {
while (resultSet.next()) {
System.out.printf(
"%d %s %f\n",
resultSet.getLong("VenueId"),
resultSet.getString("VenueName"),
resultSet.getDouble("PopularityScore"));
}
}
}Node.js
Spanner용 클라이언트 라이브러리를 설치하고 사용하는 방법은 Spanner 클라이언트 라이브러리를 참조하세요.
// Imports the Google Cloud client library.
const {Spanner} = require('@google-cloud/spanner');
/**
* TODO(developer): Uncomment the following lines before running the sample.
*/
// const projectId = 'my-project-id';
// const instanceId = 'my-instance';
// const databaseId = 'my-database';
// Creates a client
const spanner = new Spanner({
projectId: projectId,
});
// Gets a reference to a Cloud Spanner instance and database.
const instance = spanner.instance(instanceId);
const database = instance.database(databaseId);
const fieldType = {
type: 'float64',
};
const exampleFloat = Spanner.float(0.8);
const query = {
sql: `SELECT VenueId, VenueName, PopularityScore FROM Venues
WHERE PopularityScore > @popularityScore`,
params: {
popularityScore: exampleFloat,
},
types: {
popularityScore: fieldType,
},
};
// Queries rows from the Venues table.
try {
const [rows] = await database.run(query);
rows.forEach(row => {
const json = row.toJSON();
console.log(
`VenueId: ${json.VenueId}, VenueName: ${json.VenueName},` +
` PopularityScore: ${json.PopularityScore}`
);
});
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}PHP
Spanner용 클라이언트 라이브러리를 설치하고 사용하는 방법은 Spanner 클라이언트 라이브러리를 참조하세요.
use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Database;
/**
* Queries sample data from the database using SQL with a FLOAT64 parameter.
* Example:
* ```
* query_data_with_float_parameter($instanceId, $databaseId);
* ```
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function query_data_with_float_parameter(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$exampleFloat = 0.8;
$results = $database->execute(
'SELECT VenueId, VenueName, PopularityScore FROM Venues ' .
'WHERE PopularityScore > @popularityScore',
[
'parameters' => [
'popularityScore' => $exampleFloat
]
]
);
foreach ($results as $row) {
printf('VenueId: %s, VenueName: %s, PopularityScore: %f' . PHP_EOL,
$row['VenueId'], $row['VenueName'], $row['PopularityScore']);
}
}Python
Spanner용 클라이언트 라이브러리를 설치하고 사용하는 방법은 Spanner 클라이언트 라이브러리를 참조하세요.
# instance_id = "your-spanner-instance"
# database_id = "your-spanner-db-id"
spanner_client = spanner.Client()
instance = spanner_client.instance(instance_id)
database = instance.database(database_id)
exampleFloat = 0.8
param = {"popularity_score": exampleFloat}
param_type = {"popularity_score": param_types.FLOAT64}
with database.snapshot() as snapshot:
results = snapshot.execute_sql(
"SELECT VenueId, VenueName, PopularityScore FROM Venues "
"WHERE PopularityScore > @popularity_score",
params=param,
param_types=param_type,
)
for row in results:
print("VenueId: {}, VenueName: {}, PopularityScore: {}".format(*row))Ruby
Spanner용 클라이언트 라이브러리를 설치하고 사용하는 방법은 Spanner 클라이언트 라이브러리를 참조하세요.
# project_id = "Your Google Cloud project ID"
# instance_id = "Your Spanner instance ID"
# database_id = "Your Spanner database ID"
require "google/cloud/spanner"
spanner = Google::Cloud::Spanner.new project: project_id
client = spanner.client instance_id, database_id
sql_query = "SELECT VenueId, VenueName, PopularityScore FROM Venues
WHERE PopularityScore > @popularity_score"
params = { popularity_score: 0.8 }
param_types = { popularity_score: :FLOAT64 }
client.execute(sql_query, params: params, types: param_types).rows.each do |row|
puts "#{row[:VenueId]} #{row[:VenueName]} #{row[:PopularityScore]}"
end다음 단계
다른 Google Cloud 제품의 코드 샘플을 검색하고 필터링하려면 Google Cloud 샘플 브라우저를 참조하세요.