Penomoran halaman kueri

Menjalankan kueri dan mendapatkan baris menggunakan penomoran halaman otomatis.

Jelajahi lebih lanjut

Untuk dokumentasi mendetail yang menyertakan contoh kode ini, lihat artikel berikut:

• Menggunakan penomoran halaman dengan BigQuery API

Contoh kode

Java

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan Java di Panduan memulai BigQuery menggunakan library klien. Untuk mengetahui informasi selengkapnya, lihat Dokumentasi referensi BigQuery Java API.

Untuk melakukan autentikasi ke BigQuery, siapkan Kredensial Default Aplikasi. Untuk mengetahui informasi selengkapnya, lihat Menyiapkan autentikasi untuk library klien.

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

// Sample to run query with pagination.
public class QueryPagination {

  public static void main(String[] args) {
    String datasetName = "MY_DATASET_NAME";
    String tableName = "MY_TABLE_NAME";
    String query =
        "SELECT name, SUM(number) as total_people"
            + " FROM `bigquery-public-data.usa_names.usa_1910_2013`"
            + " GROUP BY name"
            + " ORDER BY total_people DESC"
            + " LIMIT 100";
    queryPagination(datasetName, tableName, query);
  }

  public static void queryPagination(String datasetName, String tableName, String query) {
    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();

      TableId tableId = TableId.of(datasetName, tableName);
      QueryJobConfiguration queryConfig =
          QueryJobConfiguration.newBuilder(query)
              // save results into a table.
              .setDestinationTable(tableId)
              .build();

      bigquery.query(queryConfig);

      TableResult results =
          bigquery.listTableData(tableId, BigQuery.TableDataListOption.pageSize(20));

      // First Page
      results
          .getValues()
          .forEach(row -> row.forEach(val -> System.out.printf("%s,\n", val.toString())));

      while (results.hasNextPage()) {
        // Remaining Pages
        results = results.getNextPage();
        results
            .getValues()
            .forEach(row -> row.forEach(val -> System.out.printf("%s,\n", val.toString())));
      }

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

Python

Sebelum mencoba contoh ini, ikuti petunjuk penyiapan Python di Panduan memulai BigQuery menggunakan library klien. Untuk mengetahui informasi selengkapnya, lihat Dokumentasi referensi BigQuery Python API.

Untuk melakukan autentikasi ke BigQuery, siapkan Kredensial Default Aplikasi. Untuk mengetahui informasi selengkapnya, lihat Menyiapkan autentikasi untuk library klien.

from google.cloud import bigquery

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

query = """
    SELECT name, SUM(number) as total_people
    FROM `bigquery-public-data.usa_names.usa_1910_2013`
    GROUP BY name
    ORDER BY total_people DESC
"""
query_job = client.query(query)  # Make an API request.
query_job.result()  # Wait for the query to complete.

# Get the destination table for the query results.
#
# All queries write to a destination table. If a destination table is not
# specified, the BigQuery populates it with a reference to a temporary
# anonymous table after the query completes.
destination = query_job.destination

# Get the schema (and other properties) for the destination table.
#
# A schema is useful for converting from BigQuery types to Python types.
destination = client.get_table(destination)

# Download rows.
#
# The client library automatically handles pagination.
print("The query data:")
rows = client.list_rows(destination, max_results=20)
for row in rows:
    print("name={}, count={}".format(row["name"], row["total_people"]))

Rust

use google_cloud_bigquery::client::BigQuery;

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

    let mut rows = client
        .query(
            r#"
SELECT name
FROM `bigquery-public-data.usa_names.usa_1910_2013`
WHERE state = 'TX'
LIMIT 2500
"#,
        )
        .with_project_id(project_id)
        .set_page_size(1000_u32)
        .set_location("US")
        .until_done()
        .await?
        .read()
        .set_page_size(1000);

    let mut count = 0;
    while let Some(row) = rows.next().await.transpose()? {
        let _name: String = row.get("name")?;
        count += 1;
    }
    println!("Total rows fetched via pagination: {count}");
    Ok(())
}

Langkah berikutnya

Untuk menelusuri dan memfilter contoh kode untuk produk Google Cloud lainnya, lihat browser contohGoogle Cloud .