Using a MySQL join

Question

A user can have two types of relationships on my website. Following or Friends. I want to populate each user's news feed with the posts from users they have a relationship with. So far I have this join:

SELECT  * 
FROM    posts a 
        LEFT JOIN relationships b
            ON a.user_id = b.user_2
WHERE   b.user_1 = $user_id AND 
    b.status IN (1,3,4) OR a.user_id = $user_id
ORDER BY a.post_id DESC

b.status is the column from my relationships table that determines the status of the relationship between two users. 1 being following, 3 being friends, 4 being following with a pending friend request. My join works well, except that It it doesn't take into consideration that there is only one row in my 'relationships' table that can represent a friend ship between any two people. There are two rows for following. The first being user 1(mark) following user 2(matt) and user 2(matt) following user 1(mark). But with friendships it is either a row stating one way or the other, with a status of 3. First off, is that smart practice? Or should I have two rows for this type pf relationship as well? Secondly, how can I make my JOIN QUERY also grab posts from users with where there is a relationship between user_1 and user_2 and the status = 3? With no regard to the order user_1 and user_2 are in?

Table Structure:

Posts:

| user_id | post_id | story |
-----------------------------
|  1      |  1      | text. |
-----------------------------

Relationships:

| rel_id  | user_1  | user_2| status |
--------------------------------------
|  1      |  1      |   2   |    3   |
--------------------------------------

Answer 1

In your WHERE statement, do something like this so you match either column in the relationship table. The OR gets both of them.

WHERE   b.user_1 = $user_id OR b.user_2 = $user_id 

Good luck!