PHP mysql how to relationship three tables showing outputs from different tables

Question

I have this diagram

What I wanna do is have this output:

How do you manage to do the query of this one?

I have this code

SELECT users.firstname, users.lastname, 
       users.screenname, posts.post_id, posts.user_id,
       posts.post, posts.upload_name, 
       posts.post_type, posts.date_posted
FROM website.users users
INNER JOIN website.posts posts ON (users.user_id = posts.user_id)
ORDER BY posts.pid DESC
//PROBLEM with this one is that it only views the post from all users.

//SO I added
SELECT COUNT(user_id) AS friends, SUM(user_id = ?) AS you, user_id
FROM feeds WHERE post_id = ?
//This one will give you two fields containing how many different users **feeds** the
post

Please help guys. Actually this one I am just following Facebook's "LIKE" status the only thing is I'm not an amateur with this kind of stuff so I'd be glad to hear all your answers. I really need your help

Answer 1

If I've understood you correctly, you want an outer join with the feeds table (in order to retain all posts even if there are no associated feeds), then GROUP BY post.pid in order to amalgamate together all such feeds for each post, and SELECT the desired information.

I use MySQL's GROUP_CONCAT() function to obtain a comma-separated list of all users (up to group_concat_max_len) who have a "feed" for the given post (you can change the delimiter with the SEPARATOR modifier, if so desired).

SELECT users.firstname, users.lastname, 
       users.screenname, posts.post_id, posts.user_id,
       posts.post, posts.upload_name, 
       posts.post_type, posts.date_posted,
       COUNT(feeds.user_id) AS friends,   -- number of "likes"
       SUM(feeds.user_id = ?) AS you,     -- did I like this?
       GROUP_CONCAT(feeds.user_id)        -- who likes it?
FROM website.users users
INNER JOIN website.posts posts ON (users.user_id = posts.user_id)
LEFT  JOIN website.feeds feeds ON (posts.post_id = feeds.post_id)
GROUP BY posts.pid
ORDER BY posts.pid DESC

---

UPDATE

To obtain the full name of users who have "liked" the post, excluding oneself, one needs to join the users table a second time:

SELECT users.firstname, users.lastname, 
       users.screenname, posts.post_id, posts.user_id,
       posts.post, posts.upload_name, 
       posts.post_type, posts.date_posted,
       COUNT(feeds.user_id) AS friends,                      -- number of "likes"
       SUM(feeds.user_id = ?) AS you,                        -- did I like this?
       GROUP_CONCAT(
         CASE WHEN NOT likes.user_id = ? THEN                -- exclude self
           CONCAT_WS(' ', likes.firstname, likes.lastname)   -- full names
         END
       )
FROM website.users users
INNER JOIN website.posts posts ON (users.user_id = posts.user_id)
LEFT  JOIN website.feeds feeds ON (posts.post_id = feeds.post_id)
LEFT  JOIN website.users likes ON (feeds.user_id = likes.user_id)
GROUP BY posts.pid
ORDER BY posts.pid DESC