Question

我正在关注https://cloud.google.com/bigquery/create-simple-app-api#bigquery-simple-app-java中给出的示例，以获取BigQuery API的查询结果。

TableResult result = queryJob.getQueryResults();

它以TableResults类型返回结果，但我需要以json格式得到结果。

TableResult{rows=[[FieldValue{attribute=PRIMITIVE, value=(...)},
    FieldValue{attribute=PRIMITIVE, value=(...)},
    FieldValue{attribute=PRIMITIVE, value=(...)},
    FieldValue{attribute=PRIMITIVE, value=(...)},
    FieldValue{attribute=PRIMITIVE, value=(...)},
    FieldValue{attribute=PRIMITIVE, value=(...)},
    FieldValue{attribute=PRIMITIVE, value=(...)}],(...)

如何将TableResults类型的结果转换为json，甚至csv？

Answer 1

要将表格中的行转换为JSON，您可以使用函数TO_JSON_STRING [1]。要获取带格式的JSON，您需要将参数“true”传递给函数。

新查询如下所示：

#standardSQL
“SELECT TO_JSON_STRING(t,true)"
 + "FROM ( 
    SELECT CONCAT('https://stackoverflow.com/questions/', CAST(id as STRING)) as url, "
     + "view_count "
     + "FROM `bigquery-public-data.stackoverflow.posts_questions` "
     + "WHERE tags like '%google-bigquery%' "
     + "ORDER BY favorite_count DESC LIMIT 10) as t”

输出：

TableResult{rows=[[FieldValue{attribute=PRIMITIVE, value={
  "url": "https://stackoverflow.com/questions/6607552",
  "view_count": 24524
}}], [FieldValue{attribute=PRIMITIVE, value={
  "url": "https://stackoverflow.com/questions/20349189",
  "view_count": 4298
}}], [FieldValue{attribute=PRIMITIVE, value={
  "url": "https://stackoverflow.com/questions/22734777",
  "view_count": 7940
}}], [FieldValue{attribute=PRIMITIVE, value={
  "url": "https://stackoverflow.com/questions/27537720",
  "view_count": 2039
(...)

如何使用BigQuery API从json中的TableResult获取查询结果

1 个答案: