mysql - 如何将来自不同子查询的多个SUM加到一个结果中？

如何在MySQL的不同子查询中添加SUM？

JOIN ( SELECT SUM(IF(isPurchased='0', 1, 0)) AS numQuotes, customer_id FROM product1_quote GROUP BY customer_id ) p1q ON (p1q.customer_id = c.customer_id)

JOIN ( SELECT SUM(IF(isPurchased='0', 1, 0)) AS numQuotes, customer_id FROM product2_quote GROUP BY customer_id ) p1q ON (p1q.customer_id = c.customer_id)

所以我想将这两个加起来，并将numQuotes作为总数numQuotes。但是，这要复杂得多，因为不同表的数量是动态的，因此在任何给定情况下都可以有任意数量的子查询。

最佳答案

以下是什么？

select sum(numQuotes), customer_id from
(
  (SELECT SUM(IF(isPurchased='0', 1, 0)) AS numQuotes, customer_id FROM
  product1_quote GROUP BY customer_id ) p1q ON (p1q.customer_id = c.customer_id)
UNION
  (SELECT SUM(IF(isPurchased='0', 1, 0)) AS numQuotes, customer_id FROM
  product2_quote GROUP BY customer_id ) p1q ON (p1q.customer_id = c.customer_id)
) group by customer_id;

括号可能已关闭，因此请先检查它们。

关于mysql - 如何将来自不同子查询的多个SUM加到一个结果中？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/3626336/