按用户对选择销售

Question

我有一个会话表

    UserId    SessionId
    1         a
    2         a
    1         b
    4         b
    2         c
    3         c

另一个销售额与SessionID挂钩的销售表。我希望通过Session表中的唯一用户对来获得销售，而无需使用游标。

Answer 1

SELECT  ss1.userid, ss2.userid, SUM(sales)
FROM    session ss1
JOIN    session ss2
ON      ss2.sessionid = ss1.sessionid
        AND ss2.userid < ss1.userid
JOIN    sales s
ON      s.sessionid = ss1.sessionid
GROUP BY
        ss1.userid, ss2.userid