我正在寻找一种从多表中选择多数据的方法WHERE uid = :uid并通过data sort它们.
像这样的事情：
SELECT * FROM
(SELECT * from comments) AND
(SELECT * from likes) AND
(SELECT * from photos) AND
(SELECT * from messages) WHERE uid = :uid ORDER BY date LIMIT 30
实际上，在个人资料时间轴中，我需要显示likes，comments，photos和...所有这些部分都应该sort by date limitation......
编辑：
Select cid,comment,pid,date from `ctg_comments` where uid = 69
UNION
Select pid,date from `ctg_likes` where uid = 69
UNION
Select address,postid,date from `ctg_photos` where byuid = 69
UNION
Select postid,date from `ctg_reservation` where uid=69
Order by date limit 30
我需要每个表列中的一些，但它们与使用 UNION 不同。
谢谢。
Select * from comments where uid=:uid
UNION
Select * from likes where uid:uid
UNION
Select * from photos where uid:uid
UNION
Select * from messages where uid:uid
Order by date limit 30
此解决方案要求每个表中的列具有相同的类型，结果集将采用第一个表的列名。如果每个表上只有一个或两个列不同，则可以通过命名来提取相似的列，而不是提取所有列：http://dev.mysql.com/doc/refman/5.7/en/union.html
提取带有 * 的所有列通常是不受欢迎的，因为您的代码在不知道数据库的情况下变得不可读。它可能会提取比需要的更多的数据。
对于您的数据结构，您可能想尝试一下(我猜了列类型，因此如果需要，请更正(：
Select 'comment' as type, 'none' as address, cid, comment, pid, date from `ctg_comments` where uid = 69
UNION
Select 'like' as type, 'none' as address, -1 as cid, 'none' as comment, pid, date from `ctg_likes` where uid = 69
UNION
Select 'photo'as type, address, -1 as cid, postid as pid, 'none' as comment, date from `ctg_photos` where byuid = 69
UNION
Select 'reservation' as type, 'none' as address, -1 as cid, postid as pid, 'none' as comment, date from `ctg_reservation` where uid=69
Order by date limit 30
我添加了一个类型列，以便在 php 之后更容易处理(您只需使用开关大小写测试此字段，而不是测试地址是否 == 'none' 或 cid == -1 ...