I'm trying to make a homepage somewhat like Facebook, I made it so it could show the posts from the people I follow, but I couldn't see my own posts as I can't follow myself. Here is the line of SQL code I've written (it contains PHP variables):
SELECT *
FROM user_posts
INNER JOIN user_following ON user_posts.username = user_following.username
WHERE user_following.follower = '$me->username'
ORDER BY id DESC
LIMIT 0, 15
user_posts
table contains all the posts.user_following
table contains all follow data, where username
is the user being followed, and the follower
is the user following the username
$me->username
is the username of the user logged in.user_following
table structure:
Thanks, in advance!
There's a couple of different ways to skin this query:
Sub-query
SELECT *
FROM user_posts
WHERE user_posts.username = 'bob'
OR user_posts.username IN(
SELECT username
FROM user_following
WHERE user_posts.username = user_following.username
)
LIMIT 0, 15
http://sqlfiddle.com/#!9/6bf2c6/9
Use the Users Table
Requires GROUP BY
or DISTINCT user_posts.id
, which are non-optimal.
SELECT
user_posts.*
FROM users
LEFT JOIN user_following ON users.username = user_following.username
INNER JOIN user_posts ON (
users.username = user_posts.username
OR user_following.follower = user_posts.username
)
WHERE users.username = 'bob'
GROUP BY user_posts.id
LIMIT 0, 15
http://sqlfiddle.com/#!9/d91be/1
IMPORTANT! Make sure and index those columns in your table. Otherwise, performance will suffer as the tables get bigger (especially user_following
).