[Err] 1093 - You can't specify target table 'user' for update in FROM clause

例：

UPDATE `X` SET A='' WHERE B IN ( SELECT B FROM X WHERE XXX );

会出现查询错误，调整为如下即可：(红色为查询语句，黑色部分为新增)

UPDATE `X` SET A='' WHERE B IN ( SELECT u.B FROM ( SELECT * FROM X WHERE XXX) u ) ;

来源：https://www.cnblogs.com/fan-yuan/p/12585581.html