只选择喜欢或不喜欢的特定页面？

Question

我有3张表来存储人们对喜欢和不喜欢的兴趣：pages，pages_likes，pages_dislikes

现在我希望有一个主页面来显示一个随机页面，但只有那些没有被用户喜欢或不喜欢的页面。

这是我的SQL语句：

SELECT p.id AS page_id, d.uid AS duid, l.uid AS luid, p.title FROM pages p 
JOIN pages_dislikes d on d.page_id = p.id JOIN pages_likes l on l.page_id = p.id 
WHERE d.uid != '3' AND l.uid != '3'  ORDER BY rand() LIMIT 1

但是这仍然显示一个被喜欢或不喜欢的页面，因为有其他用户喜欢或不喜欢这样的页面：

我怎样才能显示特定用户ID尚未喜欢或不喜欢的网页？

Answer 1

您的查询应该是：

SELECT 
    p.id AS page_id
    ,d.uid AS duid
    ,l.uid AS luid
    ,p.title FROM pages p 
LEFT JOIN pages_dislikes d on d.page_id = p.id 
LEFT JOIN pages_likes l on l.page_id = p.id 
WHERE (d.page_id IS null OR l.page_id is null) AND d.uid != '3' AND l.uid != '3'
ORDER BY rand() LIMIT 1

您也可以尝试此查询：

SELECT P.pageid, P.pagename FROM Pages P LEFT JOIN
(
    SELECT pageid FROM lik WHERE uid <> 3
    UNION 
    SELECT pageid FROM dis WHERE uid <> 3
) LikesDislikes ON LikesDislikes.pageid = P.pageid
ORDER BY rand() LIMIT 1