问一个mysql的sql语法有关问题，多谢

问一个mysql的sql语法问题，谢谢
select   *   from   my_GroupUser   t1
  where   exists(select   *   from   my_group   t0   where   t0.id=14   and   t0.id=t1.groupId)

delete   from   my_GroupUser   t1
  where   exists(select   *   from   my_group   t0   where   t0.id=14   and   t0.id=t1.groupId)

为什么前面那句sql能执行成功，
而后面那句就错误？

区别只是一个select，一个delete，请指点一下


[解决办法]
MYSQL在刪除記錄時表好像不可以用別名
[解决办法]
学习了
[解决办法]
--try


delete my_GroupUser
from my_GroupUser t1
where exists(select * from my_group t0 where t0.id=14 and t0.id=t1.groupId)


或


delete t1
from my_GroupUser t1
where exists(select * from my_group t0 where t0.id=14 and t0.id=t1.groupId)