Question

我有一个很长的SQL查询，如下所示：

SELECT AVG(total_sum) AS avg_total_sum, COUNT(*) AS cnt
FROM (
  SELECT order_id, ...
  FROM `project.dataset.orders`
  WHERE order_id NOT IN (
    SELECT order_id
    FROM `project.dataset.orders`
    CROSS JOIN UNNEST(gifts) AS gifts
    WHERE ...
  )
)

这很好用，但我想通过将代码拆分到临时表中来简化代码，如下所示：

WITH t_ids AS (
  SELECT order_id
  FROM `project.dataset.orders`
  CROSS JOIN UNNEST(gift_details) AS gift_details
  WHERE ...
)

SELECT AVG(total_sum) AS avg_total_sum, COUNT(*) AS cnt
FROM (
  SELECT order_id, ...
  FROM `project.dataset.orders`
  WHERE order_id NOT IN t_ids
)

但这会导致以下错误：

语法错误：预期为“（”或关键字UNNEST，但标识符为“ t_ids”

我尝试添加括号UNNEST，但它似乎不适用于临时表。该问题如何解决？

Answer 1

您可以尝试以下操作

WITH t_ids AS (
    SELECT order_id
    FROM `project.dataset.orders`
    CROSS JOIN UNNEST(gifts) AS gifts
    WHERE ...+++
)
, cte as ( SELECT order_id, ...
          FROM `project.dataset.orders` t1
          join t_ids on t1.order_id=t_ids.order_id
) SELECT AVG(total_sum) AS avg_total_sum, COUNT(*) AS cnt from cte

您的WHERE order_id NOT IN t_ids这行是完全错误的，因为您没有选择任何ID，而是在where子句中使用了。顺便说一句，我已经通过使用join更改了它，因为您只需要两个表的通用ID，即可内部联接

Answer 2

我刚刚注意到，我可以简单地将NOT IN t_ids替换为NOT IN (SELECT order_id FROM t_ids)：

WITH t_ids AS (
  SELECT order_id
  FROM `project.dataset.orders`
  CROSS JOIN UNNEST(gift_details) AS gift_details
  WHERE ...
)

SELECT AVG(total_sum) AS avg_total_sum, COUNT(*) AS cnt
FROM (
  SELECT order_id, ...
  FROM `project.dataset.orders`
  WHERE order_id NOT IN (SELECT order_id FROM t_ids)
)

最后，代码既可以正常运行，又看起来不错！但是，如果有人有更简短的解决方案，我会很乐意接受。

BigQuery：在临时表中

2 个答案: