MySQL 查询所有尚未关注或尚未刷卡的用户

Question

所以我有下表

USERS 
user_id /name/bio

FOLLOWERS 
user_id_fk/following_uid_fk

SWIPED
user_id_fk/ swiped_on_uid_fk

我想查询用户尚未关注并且过去尚未滑动过的所有用户，但我在想象它会如何进行时遇到了一些麻烦。

这是我的第一次尝试:

SELECT a.user_id, a.name
FROM users AS a, FOLLOWERS AS b, SWIPES AS c
WHERE a.user_id != b.swiped_on_user
  AND b.user_id_fk = '1'
  AND c.user_id_fk = '1'
  AND c.SWIPPED_user_id != a.user_id
LIMIT 0 , 30

Answer 1

我认为您需要这样的查询:

SELECT 
    u.user_id, u.name
FROM
    users As u
WHERE
    NOT u.user_id IN (
        SELECT
            user_id_fk
        FROM
            swiped)
    AND
    NOT u.user_id IN (
        SELECT
            user_id_fk
        FROM
            followers)
LIMIT 0, 30;