You can't specify target table for update in FROM clause 问题

Mysql 修改或者删除一个表的条件如果是 这个表的子查询，可能会出现下面这个错误：

You can’t specify target table for update in FROM clause

这个意思是不能查询这个表的同时修改这个表的信息。

解决方法是在子查询的外部，在套一层查询。

例如

DELETE
FROM


test 


WHERE

id IN (
	SELECT
			w2.id AS id 
		FROM
			test AS w1
			INNER JOIN test AS w2 ON w1.id < w2.id 
			AND w1.content = w2.content 


);

这样会出错。

应该改成下面这样

DELETE
FROM


test


WHERE

id IN (
	SELECT
		a.id 
	FROM
		(
		SELECT
			w2.id AS id 
		FROM
			test AS w1
			INNER JOIN test AS w2 ON w1.id < w2.id 
			AND w1.content = w2.content 
			) as a


);