将 Google BigQuery 中的表与 UNION ALL 合并

Question

我想在 BQ 中做这样的事情。这些表具有不同的模式。任何想法如何实现这一目标？

SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID, Withdrawal_this_hour FROM `tb1`
UNION ALL
SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID, Refill_this_hour FROM `tb2` 
UNION ALL
SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID, changes_this_hour, net_amount, date from `tb3`

提前谢谢..

Answer 1

列必须相同，所以是这样的：

SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID,
       Withdrawal_this_hour, NULL as Refill_this_hour,
       NULL as changes_this_hour, NULL as net_amount, NULL as date 
FROM `tb1`
UNION ALL
SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID,
       NULL, Refill_this_hour, NULL, NULL, NULL
FROM `tb2` 
UNION ALL
SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID,
       NULL, NULL, changes_this_hour, net_amount, date 
FROM `tb3`

Answer 2

对于联合所有列数及其数据对于所有表big query docs 必须相同，您可以使用 cte 尝试如下所示

  with cte as  (

   SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID,
   Withdrawal_this_hour, NULL as Refill_this_hour,
   NULL as changes_this_hour, NULL as net_amount, NULL as date
  UNION ALL
  SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID,
   NULL, Refill_this_hour, NULL, NULL, NULL FROM tb2
   UNION ALL
  SELECT YYYYMMDDHH, CONTAINER, Parent_Container, PROTOTYPE_ID,
   NULL, NULL, changes_this_hour, net_amount, date 
  FROM tb3
 ) select * from cte