php - mysql查询帮助？

Question

(
  SELECT u.username, u.picture, m.id, m.user_note, m.reply_id, m.reply_name, m.dt
  FROM   relationships r
  JOIN notes m ON m.user_id = r.leader
  JOIN user u ON r.leader = u.user_id
  WHERE r.listener ='2'
)


UNION ALL
(
  SELECT u.username, u.picture, m.id, m.user_note, m.reply_id, m.reply_name, m.dt
  FROM   notes m
  JOIN user u ON m.user_id = u.user_id
  WHERE u.user_id ='2'
)
WHERE dt > '2010-09-20_131830'
ORDER BY dt DESC

这个 deos 是什么，它查询用户(登录)、他们关注的人并检索他们的消息。表格如下所示，!

我想添加到此查询的是用户(登录)更新。但显然用户不关注自己。最好的方法是什么!!

用户表

 user_id | username
 -------------------
       1 | solomon
       2 | muna

消息表

id    user_id| message
---------------------------------------
 1       1   | this is my first message
 2       1   | this is my second message
 3       2   | this is muna message    

关系表

leader | follower
------------------
     1 | 2

Answer 1

这个怎么样:

SELECT u.username, u.picture, m.id, m.user_note, m.reply_id, m.reply_name, m.dt
FROM notes m
INNER JOIN user u
ON m.user_id = u.user_id
WHERE (m.user_id = '".$_SESSION['user_id']."'
OR m.userID IN (
   SELECT r.leader
   FROM relationships r
   WHERE r.listener ='".$_SESSION['user_id']."'))