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

 翻译：MySQL不能指定更新的目标表在FROM子句

源SQL语句：

delete from t_official_sys_user
where USER_NAME IN(SELECT USER_NAME FROM t_official_sys_user b group by b.`USER_NAME` having  count(1) > 1)

执行报以下错误：

[SQL] 

delete from t_official_sys_user
where USER_NAME IN(SELECT USER_NAME FROM t_official_sys_user b group by b.`USER_NAME` having  count(1) > 1)

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

解决代码如下：

delete from t_official_sys_user
where USER_NAME IN(select USER_NAME from ( SELECT USER_NAME FROM t_official_sys_user b group by b.`USER_NAME` having  count(1) > 1) as temtable );

分析：

先把要删除的目标放到一张临时表再把要删除的条件指定到这张临时表即可。