Question

我正在尝试选择userName和groupId重复的所有行，而userId不是该userName / groupId组合的最大userId。到目前为止，这是我的代码：

select *
from userTable u
where exists
    (select *
    from userTable u1
    where userName <> '' and userName is not null
    and u.userName = u1.userName and u.groupId = u1.groupId
    and u.userId <> max(u1.userId)
    group by userName, groupId
    having count(*) > 1)
order by userName

但是，行：

and u.userId <> u1.max(userId)

给我一个错误。

执行此查询的正确方法是什么？

Answer 1

SELECT  u.*
FROM    (
        SELECT  userName, groupId, MAX(userId) AS maxId
        FROM    userTable
        GROUP BY
                userName, groupId
        HAVING  COUNT(*) > 1
        ) q
JOIN    userTable u
ON      u.userName = q.userName
        AND u.groupId = q.groupId
        AND u.userId <> q.maxId

Answer 2

我应该这样做，我想：

select t.*
from dbo.UserTable t
join ( select userName , groupID , maxUserID = max(userID)
       from dbo.UserTable x
       group by userName , groupID
       having count(*) > 1
     ) dupes on dupes.userName  = t.userName
            and dupes.groupID   = t.groupID
            and dupes.maxUserID > t.userID

相关查询：选择条件不是最大值（内部查询中的条件）

2 个答案: