Question

所以我有两个MySQL查询，如果我知道要结合我会，但我不会这样，为什么我转向＆＃34; SO＆＃34;，在那种情况下我没有尝试任何东西，因为它超出了我的范围。我希望将所有问题合并在一起，如果不可能，请告诉我。

查询一个＆＃34;这将选择您的所有朋友帖子，包括您的帖子＆＃34;：

"SELECT b.*, c.photo, d.name, e.status 
FROM post b 
INNER JOIN profile c 
INNER JOIN user d 
INNER JOIN user_friendship e 
ON b.from_user = c.user_id 
AND b.from_user = d.id 
AND e.friend_id = b.from_user 
WHERE e.status = :status 
AND e.user_id = :id
ORDER BY b.id DESC LIMIT 20"

查询二＆＃34;这会选择以下帖子的所有人＆＃34;：

"SELECT b.*, c.photo, d.name, e.status
FROM post b
INNER JOIN profile c 
INNER JOIN user d 
INNER JOIN user_follower e 
ON b.from_user = c.user_id 
AND b.from_user = d.id 
AND e.to_id = b.from_user 
WHERE e.status = :status 
AND e.who_id = :id
ORDER BY b.id DESC LIMIT 20"

我已将这些结合起来，但仅限于php。我想在一个MySQL查询中结合使用。提前致谢

Answer 1

SELECT *
FROM
  (SELECT b.*,
          c.photo,
          d.name,
          e.status
   FROM post b
   INNER JOIN profile c
   INNER JOIN USER d
   INNER JOIN user_friendship e ON b.from_user = c.user_id
   AND b.from_user = d.id
   AND e.friend_id = b.from_user
   WHERE e.status = :status
     AND e.user_id = :id LIMIT 20
   UNION SELECT b.*,
                c.photo,
                d.name,
                e.status
   FROM post b
   INNER JOIN profile c
   INNER JOIN USER d
   INNER JOIN user_follower e ON b.from_user = c.user_id
   AND b.from_user = d.id
   AND e.to_id = b.from_user
   WHERE e.status = :status
     AND e.who_id = :id LIMIT 20 ) MainQuery
ORDER BY id DESC

Answer 2

SELECT b.*, c.photo, d.name, e.status, "P" 
FROM post b 
INNER JOIN profile c 
INNER JOIN user d 
INNER JOIN user_friendship e 
ON b.from_user = c.user_id 
AND b.from_user = d.id 
AND e.friend_id = b.from_user 
WHERE e.status = :status 
AND e.user_id = :id
ORDER BY b.id DESC LIMIT 20
UNION
SELECT b.*, c.photo, d.name, e.status, "F"
FROM post b
INNER JOIN profile c 
INNER JOIN user d 
INNER JOIN user_follower e 
ON b.from_user = c.user_id 
AND b.from_user = d.id 
AND e.to_id = b.from_user 
WHERE e.status = :status 
AND e.who_id = :id
ORDER BY b.id DESC LIMIT 20

使用额外的列，您可以看到行的来源（P = post，F = follow）

请记住，union将删除重复的行。如果您想查看所有行，请使用UNION ALL

如何组合2个复杂的mysql查询

2 个答案: