sql - SQL 选择好友更改列名

Question

我试图在 MS SQL 上选择带有 MemberID 的朋友列表，这是我的代码

    SELECT MemberID, FriendID,(Select Username From Members Where MemberID = Friends.FriendID) as Username FROM Friends WHERE MemberID = @MemberID
    UNION
    SELECT MemberID as FriendID, FriendID as MemberID,(Select Username From Members Where MemberID = Friends.MemberID) as Username FROM Friends WHERE FriendID = @MemberID

结果是

MemberID    FriendID  
1           2
1           7
34          1

我应该怎么做才能将最后一行更改为

MemberID    FriendID  
1           2
1           7
1           34

谢谢！

Answer 1

SELECT  MemberID, FriendID
FROM    Friends
WHERE   MemberID = @MemberID
UNION ALL
SELECT  FriendID, MemberID
FROM    Friends
WHERE   FriendID = @MemberID