mysql - 查询中有什么问题

Question

我正在尝试触发以下查询...

有什么问题吗？

delete from user_role 
WHERE user_id in (
    select u.user_id from user u, user_role ur 
    where u.USER_ID=ur.USER_ID and ur.ROLE_ID=4 and u.USER_ID not in (
        select user_id from referrers));

Answer 1

如手册部分所述DELETE Syntax :

Currently, you cannot delete from a table and select from the same table in a subquery.

您可以改为使用 DELETE 和 join 的多表形式把你的 table 放在一起:

DELETE user_role
FROM   user_role
  INNER JOIN user_id   USING (USER_ID)
  LEFT  JOIN referrers USING (USER_ID)
WHERE user_role.ROLE_ID = 4 AND referrers.USER_ID IS NULL