Parametri posizionali e tipi forniti

Esegui una query con parametri posizionali e tipi di parametri forniti.

Esempio di codice

Java

Prima di provare questo esempio, segui le istruzioni di configurazione Java nella guida rapida di BigQuery per l'utilizzo delle librerie client. Per saperne di più, consulta la documentazione di riferimento dell' API Java di BigQuery.

Per eseguire l'autenticazione in BigQuery, configura le Credenziali predefinite dell'applicazione. Per saperne di più, vedi Configura l'autenticazione per le librerie client.

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.StandardSQLTypeName;
import com.google.cloud.bigquery.TableResult;

// Sample to run query with positional types parameters.
public class QueryWithPositionalTypesParameters {

  public static void main(String[] args) {
    String[] words = {"and", "is", "the", "moon"};
    String corpus = "romeoandjuliet";
    Integer wordsCount = 250;
    String query =
        "SELECT word, word_count"
            + " FROM `bigquery-public-data.samples.shakespeare`"
            + " WHERE word IN UNNEST(?)"
            + " AND corpus = ?"
            + " AND word_count >= ?"
            + " ORDER BY word_count DESC";
    queryWithPositionalTypesParameters(query, words, corpus, wordsCount);
  }

  public static void queryWithPositionalTypesParameters(
      String query, String[] words, String corpus, Integer wordsCount) {
    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();

      QueryParameterValue wordList = QueryParameterValue.array(words, StandardSQLTypeName.STRING);
      QueryParameterValue corpusParam = QueryParameterValue.of(corpus, StandardSQLTypeName.STRING);
      QueryParameterValue minWordCount =
          QueryParameterValue.of(wordsCount, StandardSQLTypeName.INT64);

      // Note: Standard SQL is required to use query parameters.
      QueryJobConfiguration queryConfig =
          QueryJobConfiguration.newBuilder(query)
              .addPositionalParameter(wordList)
              .addPositionalParameter(corpusParam)
              .addPositionalParameter(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 positional types parameters performed successfully.");
    } catch (BigQueryException | InterruptedException e) {
      System.out.println("Query not performed \n" + e.toString());
    }
  }
}

Rust

use google_cloud_bigquery::client::BigQuery;
use google_cloud_bigquery::model::{QueryParameter, QueryParameterType, QueryParameterValue};

pub async fn sample(project_id: &str) -> anyhow::Result<()> {
    let client = BigQuery::builder().build().await?;

    let mut rows = client
        .query("SELECT ? AS str_col, ? AS int_col, ? AS float_col;")
        .with_project_id(project_id)
        .set_parameter_mode("POSITIONAL")
        .set_query_parameters([
            QueryParameter::new()
                .set_parameter_type(QueryParameterType::new().set_type("STRING"))
                .set_parameter_value(QueryParameterValue::new().set_value("example string")),
            QueryParameter::new()
                .set_parameter_type(QueryParameterType::new().set_type("INT64"))
                .set_parameter_value(QueryParameterValue::new().set_value("42")),
            QueryParameter::new()
                .set_parameter_type(QueryParameterType::new().set_type("FLOAT64"))
                .set_parameter_value(QueryParameterValue::new().set_value("3.14159")),
        ])
        .set_location("US")
        .run()
        .await?
        .until_done()
        .await?
        .read();

    while let Some(row) = rows.next().await.transpose()? {
        let str_col: String = row.get("str_col");
        let int_col: i64 = row.get("int_col");
        let float_col: f64 = row.get("float_col");
        println!("String: {str_col}, Int: {int_col}, Float: {float_col}");
    }
    Ok(())
}

Passaggi successivi

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