mysql - MySQL DELETE 使用 Have 和 Count 的子查询

Question

我正在尝试使用以下查询删除几个条目：

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：

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

但我得到这个错误：

您不能在 FROM 子句中指定目标表“帐户”进行更新

Answer 1

我认为您需要使用临时表来满足您的需求，如下所示：

1. Step1：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 *两个嵌套表的解决方法也可以：

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

Answer 2

您的问题已解决，只需按照以下操作即可..

    DELETE FROM account 

      WHERE guid IN 

     (SELECT * FROM 

       (SELECT guid FROM account 

          GROUP BY guid,type 

          HAVING  count(type) > 1) AS a);

Answer 3

首先创建视图

create view view_acct as 
SELECT guid FROM account 
GROUP BY guid,type HAVING count(type) > 1;

使用后视图

DELETE FROM account WHERE guid in (select * from view_acct);