MySQL: 3 table join query? -

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I have three tables (users, friends, posts) and two users (user 1 and user 2).

When user1 adds user2 as friend then user1 can simply view the post of user 2 but post only posts after date when user1 added user2 as user. My query is like: 

  $ sql = mysql_query (select from "P.P. friends at p.currentuserid = f.friendid and p. Time> f.friend_since or p> P .currentuserid = 'user1id' WHERE f.myid = 'user1id' command p.postid DESC LIMIT 20 ");

This is working perfectly but a little bit of a problem ..... !! This user2 displays users posts as user3 (as user of user 1) once, but the user shows 1 posts in several ways ....... ie 

  User2 Hi user1 Userssfsfsfsfsdf user1 Userssfsfsfsfsdf user3 Dddddddd user1 Sdfsdsdfsdsfsf user1 Sdfsdsdfsdsfsf

But why am I having this single entry / post in the database ........ !! !!

How can I fix this?

I am not a SQL expert, but I think your problem is in JOIN status. I can not see in a way that how you can get involved with posts and friends and get the results you need. A SQL expert can know this, but it is very difficult for me.

If I were you, then I would break the problem in two parts:

  1. Select user's own post

  2. Select the posts of the user's friend

For example, you can do this by using 2 different positions and friends in a sub-query Join the table (I have not tested it!): 

  select p from post * p.currentuserid = 'user1id' or p.postid in P2.postid to p2.postid to p2 .currentuserid = f.friendid where p2.time & gt; = Join the PO2 friend at f.friend_since and f.myid = 'user1id ")

Another way to do this is to use a union (it did not even test Has been ..): Select 

  select posts * p.currentuserid = 'user1id' select p2. P2.currentuserid = on f.friendid where p2.time & gt; = F.friend_since and f.myid = 'user1id'

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