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：

[sql] view plain copy

print?

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] view plain copy

print?

[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：

[sql] view plain copy

print?

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。
http://blog.csdn.net/bluestarf/article/details/46622455 http://www.cnblogs.com/nick-huang/p/4412818.html