mysql - mysql中的相交或减号

Question

我有以下问题，

SELECT DISTINCT (U.uid)
FROM users U
    ,friends F
WHERE U.STATUS = '1'
    AND U.uid = F.friend_two
    AND F.friend_one = '1'
    AND F.ROLE = 'fri'

上面的查询返回 32 行。

SELECT DISTINCT (U.uid)
FROM users U
    ,friends F
WHERE U.STATUS = '1'
    AND U.uid = F.friend_one
    AND F.friend_two = '1'
    AND F.ROLE = 'fri'

上面的查询返回 15 行。

我需要合并并取相交的结果。相交的行是14行(意味着两个表中相同的U.uid是14行)

Answer 1

试试这个:

SELECT *
FROM (
    SELECT DISTINCT (U.uid) UID
    FROM users U
        ,friends F
    WHERE U.STATUS = '1'
        AND U.uid = F.friend_two
        AND F.friend_one = '1'
        AND F.ROLE = 'fri'
    ) A
INNER JOIN (
    SELECT DISTINCT (U.uid) UID
    FROM users U
        ,friends F
    WHERE U.STATUS = '1'
        AND U.uid = F.friend_one
        AND F.friend_two = '1'
        AND F.ROLE = 'fri'
    ) B ON A.UID = B.UID

这基本上是您指定的两个查询的两个结果集的用户 ID 的交集。