Follow Unfollow system

I am working on this site that follow and unfollow users just like Twitter follow. The query below works then I notice it doesn’t show me users I don’t follow because the user has been followed by somebody or is following somebody

$stmt = $mysqli->prepare("SELECT * FROM town_users LEFT JOIN user_follow_list ON user_follow_list.following_id = town_users.user_id WHERE town_users.user_id != ? AND user_follow_list.follow_id IS NULL ORDER BY RAND() LIMIT 5");
$stmt->bind_param("i", $user_id);

Below is my table structure

town_users
user_id username
| 1    | ben
| 2    | betty
| 3    | tom
| 4    | john


user_follow_list
follow_id         follower_id         following_id
|      1     |       1         |      2
|      2     |       1         |      3

In the user_follow_list Ben is following betty and tom. Now john follows a user let say tom,

follow_id         follower_id         following_id
|      3     |       4         |      3

Now the problem am having is that john doesn’t show up on ben list of users to follow.

It’s meant to show users I haven’t followed so I can follow them.

Answer

SELECT * FROM town_users 
LEFT JOIN user_follow_list ON user_follow_list.follower_id = town_users.user_id 
WHERE town_users.user_id NOT IN (SELECT following_id FROM user_follow_list WHERE 
follower_id = 1) AND town_users.user_id != 1
GROUP BY town_users.user_id ORDER BY RAND() LIMIT 5

This query will get all the user that are not being followed by ($user_id = 1).

$stmt = $mysqli->prepare("SELECT * FROM town_users 
                          LEFT JOIN user_follow_list ON user_follow_list.follower_id = town_users.user_id 
                          WHERE town_users.user_id NOT IN (SELECT following_id FROM user_follow_list WHERE follower_id = ?) 
                          AND town_users.user_id != ?
                          GROUP BY town_users.user_id ORDER BY RAND() LIMIT 5");
$stmt->bind_param("ii", $user_id, $user_id);

Here’s a SQL Fiddle: http://sqlfiddle.com/#!9/96d55/23/0