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

delete  from ExtraPrivilege
WHERE (ExtraPrivilege.PrivilegeID,ExtraPrivilege.UserID) IN 
    (SELECT ExtraPrivilege.PrivilegeID,
         ExtraPrivilege.UserID
    FROM ExtraPrivilege
   )

原因：你不能对查询的表进行修改和删除操作