MySQL DELETE 使用 Having 和 Count 的子查询

Question

我正在尝试使用以下查询删除多个条目:

首先，我使用此查询找到要删除的条目:

SELECT guid FROM account GROUP BY guid,type HAVING count(type) > 1);

然后我将此查询添加到 DELETE 语句中:

DELETE FROM account WHERE guid IN (SELECT guid FROM account GROUP BY guid,type HAVING count(type) > 1);

但是我得到这个错误:

您不能在 FROM 子句中指定要更新的目标表“account”

Answer 1

我认为您需要使用临时表来实现您的需求，如下所示:

1. 第一步:创建临时表

   CREATE TEMPORARY TABLE MyTemp
   SELECT guid FROM account 
   GROUP BY guid,type HAVING count(type) > 1;
   

2. 在删除语句中使用临时表

   DELETE FROM account 
   WHERE guid IN (SELECT guid FROM MyTemp);
   

3. 删除临时表

   DROP TEMPORARY TABLE MyTemp;
   

编辑:我认为使用 *两个嵌套表 也可以:

  DELETE FROM account 
    WHERE guid IN 
     (SELECT guid FROM 
       (SELECT guid FROM account 
       GROUP BY guid,type HAVING count(type) > 1) as MyTemp
    )