如何通过 CAST 更改 BigQuery 中嵌套字段的类型？

Question

我正在尝试从查询创建一个新表，并在此过程中转换其中一个嵌套字段。像这样的东西：

#standardSQL    
SELECT * EXCEPT (bid_info),
  (SELECT AS STRUCT bid_info.* EXCEPT (clicks), CAST(bid_info.clicks AS NUMERIC) as clicks 
  FROM `testing.fb_ads.ads`) as bid_info
FROM `testing.fb_ads.ads`

我收到错误“标量子查询生成了多个元素”，并且查询执行似乎并未结束。

我该如何解决这个查询？

Answer 1

所以，我终于找到了解决方案，如下：

SELECT * EXCEPT (bid_info),
(SELECT AS STRUCT bid_info.* EXCEPT (clicks), CAST(bid_info.clicks AS NUMERIC) as clicks ) as bid_info
FROM `testing.fb_ads.ads`