Question

我想从公共BigQuery github_repos数据集中选择所有内容，但两条记录除外：author.name AND difference.old_mode。根据我提出的类似问题，我想我想运行类似于

的查询

#standardSQL
SELECT * REPLACE ((SELECT AS STRUCT author.* EXCEPT (name)) AS author), 
REPLACE ((SELECT AS STRUCT difference.* EXCEPT (old_mode)) AS difference)
FROM `bigquery-public-data.github_repos.commits`
LIMIT 1000;

如果我运行作者排除，则效果很好：

#standardSQL
SELECT * REPLACE ((SELECT AS STRUCT author.* EXCEPT (name)) AS author)
FROM `bigquery-public-data.github_repos.commits`
LIMIT 1000;

但是，差异排除有一个错误：

#standardSQL
SELECT * REPLACE ((SELECT AS STRUCT difference.* EXCEPT (old_mode)) AS difference)
FROM `bigquery-public-data.github_repos.commits`
LIMIT 1000;

错误：

Dot-star is not supported for type ARRAY<STRUCT<old_mode INT64, new_mode INT64, old_path STRING, ...>> at [2:41]

谢谢。

更新与SQL server问题不重复。

Answer 1

作为一个独立的示例，请考虑以下问题：

WITH T AS (
  SELECT 10 AS a, ARRAY<STRUCT<x INT64, y STRING, z BOOL>>[
      (1, 'foo', true)] AS arr UNION ALL
  SELECT 11, ARRAY<STRUCT<x INT64, y STRING, z BOOL>>[
      (2, 'bar', false), (3, 'baz', true)]
)
SELECT * FROM T;

它会返回a类型的列INT64和类型为arr的列ARRAY<STRUCT<x INT64, y STRING, z BOOL>>。如果您想要返回arr的修改，其中数组中的结构省略了y，则可以使用SELECT * REPLACE和SELECT * EXCEPT的组合：

WITH T AS (
  SELECT 10 AS a, ARRAY<STRUCT<x INT64, y STRING, z BOOL>>[
      (1, 'foo', true)] AS arr UNION ALL
  SELECT 11, ARRAY<STRUCT<x INT64, y STRING, z BOOL>>[
      (2, 'bar', false), (3, 'baz', true)]
)
SELECT * REPLACE(ARRAY(SELECT AS STRUCT * EXCEPT (y) FROM UNNEST(arr)) AS arr)
FROM T;

我们的想法是用新的数组替换原始数组，我们使用ARRAY子查询与SELECT AS STRUCT和* EXCEPT来重构数组，其元素的字段为＆＃39} ; t包括y。

回到问题中的查询，您可以将相同的想法应用于difference和old_mode：

SELECT * REPLACE (
  ARRAY(SELECT AS STRUCT * EXCEPT (old_mode) FROM UNNEST(difference)) AS difference
)
FROM `bigquery-public-data.github_repos.commits`
LIMIT 1000;

查询结果包含difference数组，其结构不包含old_mode字段。

BigQuery select *除了两列

1 个答案: