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

表a 的id字段不做唯一约束，表中aa，bb字段数据重复，目前希望aa,bb字段组合确定唯一一条数据，如何删除表a中的重复数据，保留id值最小的哪一条数据。

执行sql：

delete from a where id not in (select MIN(id) as id from a GROUP BY aa,bb)

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

错误:You can't specify target table 'a' for update in FROM clause

含义:不能在同一表中查询的数据作为同一表的更新数据。

正确写法：delete from a where id not in (select * from (select MIN(id) as id from a GROUP BY aa,bb) as f)

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

查看数据：

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

数据被删除