BigQuery 选择 * 除了两列

Question

我想从公共 BigQuery github_repos 数据集中选择所有内容，但以下两条记录除外：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，它运行良好：

#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 不是 SQL server 问题的重复项。

Answer 1

作为一个独立的例子，考虑这个查询：

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;

它返回INT64 类型的列a 和ARRAY<STRUCT<x INT64, y STRING, z BOOL>> 类型的列arr。如果您想返回对arr 的修改，其中数组内的结构省略了y，您可以使用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;

我们的想法是用一个新数组替换原始数组，我们使用SELECT AS STRUCT 和* EXCEPT 的ARRAY 子查询来重构具有字段不包含y 的结构元素的数组。

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;

查询结果包含一个difference 数组，其结构不包含old_mode 字段。