Named parameters

Run a query with named parameters.

Explore further

For detailed documentation that includes this code sample, see the following:

• Running parameterized queries

Code sample

C#

Before trying this sample, follow the C# setup instructions in the BigQuery quickstart using client libraries. For more information, see the BigQuery C# API reference documentation.

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

using Google.Cloud.BigQuery.V2;
using System;

public class BigQueryQueryWithNamedParameters
{
    public void QueryWithNamedParameters(string projectId = "your-project-id")
    {
        var corpus = "romeoandjuliet";
        var minWordCount = 250;

        // Note: Standard SQL is required to use query parameters.
        var query = @"
            SELECT word, word_count
            FROM `bigquery-public-data.samples.shakespeare`
            WHERE corpus = @corpus
            AND word_count >= @min_word_count
            ORDER BY word_count DESC";

        // Initialize client that will be used to send requests.
        var client = BigQueryClient.Create(projectId);

        var parameters = new BigQueryParameter[]
        {
            new BigQueryParameter("corpus", BigQueryDbType.String, corpus),
            new BigQueryParameter("min_word_count", BigQueryDbType.Int64, minWordCount)
        };

        var job = client.CreateQueryJob(
            sql: query,
            parameters: parameters,
            options: new QueryOptions { UseQueryCache = false });
        // Wait for the job to complete.
        job = job.PollUntilCompleted().ThrowOnAnyError();
        // Display the results
        foreach (BigQueryRow row in client.GetQueryResults(job.Reference))
        {
            Console.WriteLine($"{row["word"]}: {row["word_count"]}");
        }
    }
}

Go

Before trying this sample, follow the Go setup instructions in the BigQuery quickstart using client libraries. For more information, see the BigQuery Go API reference documentation.

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

import (
	"context"
	"fmt"
	"io"

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

// queryWithNamedParams demonstrate issuing a query using named query parameters.
func queryWithNamedParams(w io.Writer, projectID string) error {
	// projectID := "my-project-id"
	ctx := context.Background()
	client, err := bigquery.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("bigquery.NewClient: %w", err)
	}
	defer client.Close()

	q := client.Query(
		`SELECT word, word_count
        FROM ` + "`bigquery-public-data.samples.shakespeare`" + `
        WHERE corpus = @corpus
        AND word_count >= @min_word_count
        ORDER BY word_count DESC;`)
	q.Parameters = []bigquery.QueryParameter{
		{
			Name:  "corpus",
			Value: "romeoandjuliet",
		},
		{
			Name:  "min_word_count",
			Value: 250,
		},
	}
	// Run the query and process the returned row iterator.
	it, err := q.Read(ctx)
	if err != nil {
		return fmt.Errorf("query.Read(): %w", err)
	}
	for {
		var row []bigquery.Value
		err := it.Next(&row)
		if err == iterator.Done {
			break
		}
		if err != nil {
			return err
		}
		fmt.Fprintln(w, row)
	}
	return nil
}

Java

Before trying this sample, follow the Java setup instructions in the BigQuery quickstart using client libraries. For more information, see the BigQuery Java API reference documentation.

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

import com.google.cloud.bigquery.BigQuery;
import com.google.cloud.bigquery.BigQueryException;
import com.google.cloud.bigquery.BigQueryOptions;
import com.google.cloud.bigquery.QueryJobConfiguration;
import com.google.cloud.bigquery.QueryParameterValue;
import com.google.cloud.bigquery.TableResult;

public class QueryWithNamedParameters {

  public static void main(String[] args) {
    queryWithNamedParameters();
  }

  public static void queryWithNamedParameters() {
    try {
      // Initialize client that will be used to send requests. This client only needs to be created
      // once, and can be reused for multiple requests.
      BigQuery bigquery = BigQueryOptions.getDefaultInstance().getService();

      String corpus = "romeoandjuliet";
      long minWordCount = 250;
      String query =
          "SELECT word, word_count\n"
              + "FROM `bigquery-public-data.samples.shakespeare`\n"
              + "WHERE corpus = @corpus\n"
              + "AND word_count >= @min_word_count\n"
              + "ORDER BY word_count DESC";

      // Note: Standard SQL is required to use query parameters.
      QueryJobConfiguration queryConfig =
          QueryJobConfiguration.newBuilder(query)
              .addNamedParameter("corpus", QueryParameterValue.string(corpus))
              .addNamedParameter("min_word_count", QueryParameterValue.int64(minWordCount))
              .build();

      TableResult results = bigquery.query(queryConfig);

      results
          .iterateAll()
          .forEach(row -> row.forEach(val -> System.out.printf("%s,", val.toString())));

      System.out.println("Query with named parameters performed successfully.");
    } catch (BigQueryException | InterruptedException e) {
      System.out.println("Query not performed \n" + e.toString());
    }
  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the BigQuery quickstart using client libraries. For more information, see the BigQuery Node.js API reference documentation.

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

// Run a query using named query parameters

// Import the Google Cloud client library
const {BigQuery} = require('@google-cloud/bigquery');
const bigquery = new BigQuery();

async function queryParamsNamed() {
  // The SQL query to run
  const sqlQuery = `SELECT word, word_count
        FROM \`bigquery-public-data.samples.shakespeare\`
        WHERE corpus = @corpus
        AND word_count >= @min_word_count
        ORDER BY word_count DESC`;

  const options = {
    query: sqlQuery,
    // Location must match that of the dataset(s) referenced in the query.
    location: 'US',
    params: {corpus: 'romeoandjuliet', min_word_count: 250},
  };

  // Run the query
  const [rows] = await bigquery.query(options);

  console.log('Rows:');
  rows.forEach(row => console.log(row));
}

Python

Before trying this sample, follow the Python setup instructions in the BigQuery quickstart using client libraries. For more information, see the BigQuery Python API reference documentation.

To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

from google.cloud import bigquery

# Construct a BigQuery client object.
client = bigquery.Client()

query = """
    SELECT word, word_count
    FROM `bigquery-public-data.samples.shakespeare`
    WHERE corpus = @corpus
    AND word_count >= @min_word_count
    ORDER BY word_count DESC;
"""
job_config = bigquery.QueryJobConfig(
    query_parameters=[
        bigquery.ScalarQueryParameter("corpus", "STRING", "romeoandjuliet"),
        bigquery.ScalarQueryParameter("min_word_count", "INT64", 250),
    ]
)
results = client.query_and_wait(
    query, job_config=job_config
)  # Make an API request.

for row in results:
    print("{}: \t{}".format(row.word, row.word_count))

What's next

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