使用并行循环汇总数据

对公共 BigQuery 数据集进行的单独查询会分别返回文档或文档集的字数。借助共享变量，可以累积字数，并在所有迭代完成后读取。

深入探索

如需查看包含此代码示例的详细文档，请参阅以下内容：

• 并行执行工作流步骤

代码示例

YAML

# Use a parallel loop to make ten queries to a public BigQuery dataset and
# use a shared variable to accumulate a count of words; after all iterations
# complete, return the total number of words across all documents
main:
  params: [input]
  steps:
    - init:
        assign:
          - numWords: 0
          - corpuses:
              - sonnets
              - various
              - 1kinghenryvi
              - 2kinghenryvi
              - 3kinghenryvi
              - comedyoferrors
              - kingrichardiii
              - titusandronicus
              - tamingoftheshrew
              - loveslabourslost
    - runQueries:
        parallel:  # 'numWords' is shared so it can be written within the parallel loop
          shared: [numWords]
          for:
            value: corpus
            in: ${corpuses}
            steps:
              - runQuery:
                  call: googleapis.bigquery.v2.jobs.query
                  args:
                    projectId: ${sys.get_env("GOOGLE_CLOUD_PROJECT_ID")}
                    body:
                      useLegacySql: false
                      query: ${"SELECT COUNT(DISTINCT word) FROM `bigquery-public-data.samples.shakespeare` " + " WHERE corpus='" + corpus + "' "}
                  result: query
              - add:
                  assign:
                    - numWords: ${numWords + int(query.rows[0].f[0].v)}  # first result is the count
    - done:
        return: ${numWords}

后续步骤

如需搜索和过滤其他 Google Cloud 产品的代码示例，请参阅 Google Cloud 示例浏览器。