Requête avec le paramètre DATE

Interroger les données à l'aide d'un paramètre DATE.

Exemple de code

C++

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

Pour vous authentifier auprès de Spanner, configurez les Identifiants par défaut de l'application. Pour en savoir plus, consultez Configurer l'authentification pour un environnement de développement local.

void QueryWithDateParameter(google::cloud::spanner::Client client) {
  namespace spanner = ::google::cloud::spanner;
  absl::CivilDay example_date(2019, 1, 1);
  spanner::SqlStatement select(
      "SELECT VenueId, VenueName, LastContactDate FROM Venues"
      " WHERE LastContactDate < @last_contact_date",
      {{"last_contact_date", spanner::Value(example_date)}});
  using RowType = std::tuple<std::int64_t, absl::optional<std::string>,
                             absl::optional<absl::CivilDay>>;
  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 << "LastContactDate: " << std::get<2>(*row).value() << "\n";
  }
  std::cout << "Query completed for [spanner_query_with_date_parameter]\n";
}

C#

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.


using Google.Cloud.Spanner.Data;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;

public class QueryWithDateAsyncSample
{
    public class Venue
    {
        public int VenueId { get; set; }
        public string VenueName { get; set; }
        public DateTime LastContactDate { get; set; }
    }

    public async Task<List<Venue>> QueryWithDateAsync(string projectId, string instanceId, string databaseId)
    {
        string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
        // Initialize a Date variable to use for querying.
        DateTime exampleDate = new DateTime(2019, 01, 01);

        using var connection = new SpannerConnection(connectionString);
        var cmd = connection.CreateSelectCommand("SELECT VenueId, VenueName, LastContactDate FROM Venues WHERE LastContactDate < @ExampleDate");
        cmd.Parameters.Add("ExampleDate", SpannerDbType.Date, exampleDate);

        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"),
                LastContactDate = reader.GetFieldValue<DateTime>("LastContactDate")
            });
        }
        return venues;
    }
}

Go

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.


import (
	"context"
	"fmt"
	"io"
	"time"

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

func queryWithDate(w io.Writer, db string) error {
	ctx := context.Background()
	client, err := spanner.NewClient(ctx, db)
	if err != nil {
		return err
	}
	defer client.Close()

	var exampleDate = civil.Date{Year: 2019, Month: time.January, Day: 1}
	stmt := spanner.Statement{
		SQL: `SELECT VenueId, VenueName, LastContactDate FROM Venues
            	WHERE LastContactDate < @lastContactDate`,
		Params: map[string]interface{}{
			"lastContactDate": exampleDate,
		},
	}
	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 lastContactDate civil.Date
		if err := row.Columns(&venueID, &venueName, &lastContactDate); err != nil {
			return err
		}
		fmt.Fprintf(w, "%d %s %v\n", venueID, venueName, lastContactDate)
	}
}

Java

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

static void queryWithDate(DatabaseClient dbClient) {
  String exampleDate = "2019-01-01";
  Statement statement =
      Statement.newBuilder(
              "SELECT VenueId, VenueName, LastContactDate FROM Venues "
                  + "WHERE LastContactDate < @lastContactDate")
          .bind("lastContactDate")
          .to(exampleDate)
          .build();
  try (ResultSet resultSet = dbClient.singleUse().executeQuery(statement)) {
    while (resultSet.next()) {
      System.out.printf(
          "%d %s %s\n",
          resultSet.getLong("VenueId"),
          resultSet.getString("VenueName"),
          resultSet.getDate("LastContactDate"));
    }
  }
}

Node.js

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

// 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: 'date',
};

const exampleDate = '2019-01-01';

const query = {
  sql: `SELECT VenueId, VenueName, LastContactDate FROM Venues
          WHERE LastContactDate < @lastContactDate`,
  params: {
    lastContactDate: exampleDate,
  },
  types: {
    lastContactDate: fieldType,
  },
};

// Queries rows from the Venues table.
try {
  const [rows] = await database.run(query);

  rows.forEach(row => {
    const date = row[2]['value'];
    const json = row.toJSON();
    console.log(
      `VenueId: ${json.VenueId}, VenueName: ${json.VenueName},` +
        ` LastContactDate: ${JSON.stringify(date).substring(1, 11)}`
    );
  });
} catch (err) {
  console.error('ERROR:', err);
} finally {
  // Close the database when finished.
  database.close();
}

PHP

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Database;

/**
 * Queries sample data from the database using SQL with a DATE parameter.
 * Example:
 * ```
 * query_data_with_date_parameter($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function query_data_with_date_parameter(string $instanceId, string $databaseId): void
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $exampleDate = '2019-01-01';

    $results = $database->execute(
        'SELECT VenueId, VenueName, LastContactDate FROM Venues ' .
        'WHERE LastContactDate < @lastContactDate',
        [
            'parameters' => [
                'lastContactDate' => $exampleDate
            ]
        ]
    );

    foreach ($results as $row) {
        printf('VenueId: %s, VenueName: %s, LastContactDate: %s' . PHP_EOL,
            $row['VenueId'], $row['VenueName'], $row['LastContactDate']);
    }
}

Python

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

# 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)

exampleDate = "2019-01-01"
param = {"last_contact_date": exampleDate}
param_type = {"last_contact_date": param_types.DATE}

with database.snapshot() as snapshot:
    results = snapshot.execute_sql(
        "SELECT VenueId, VenueName, LastContactDate FROM Venues "
        "WHERE LastContactDate < @last_contact_date",
        params=param,
        param_types=param_type,
    )

    for row in results:
        print("VenueId: {}, VenueName: {}, LastContactDate: {}".format(*row))

Ruby

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

# 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, LastContactDate FROM Venues
             WHERE LastContactDate < @last_contact_date"

params      = { last_contact_date: "2019-01-01" }
param_types = { last_contact_date: :DATE }

client.execute(sql_query, params: params, types: param_types).rows.each do |row|
  puts "#{row[:VenueId]} #{row[:VenueName]} #{row[:LastContactDate]}"
end

Étapes suivantes

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