delete from student where id NOT in ( select min(id) id from student group by name,stuid,subid,subname,score );
当在mysql中执行这条语句时，报错：You can‘t specify target table ‘student‘ for update in FROM clause；
原因是子查询中使用student表进行查询，而外层的delete语句也是对student进行的操作，因此报错。
解决办法：
将子查询再包装一次：
delete from student where id NOT in ( select * from ( select min(id) id from student group by name,stuid,subid,subname,score )a );
注意：这种错误只出现在mySQL中。
参考：http://blog.csdn.net/priestmoon/article/details/8016121
mySQL: delete 语句报错 You can't specify target table 'student' for update in FROM clause
原文：http://www.cnblogs.com/HapLe0/p/7761016.html