Question

I’m trying to make an application that pairs two available users by selecting them randomly from a database and then making them unavailable (so they can’t be selected again).

I was wondering how I could select them and then pair them?

I’ve got the following database structure.

USERS
| id        | autoincrement, primary key
| user_id   | user's ID
| connected | available, connecting, chatting


ROOMS
| id        | 
| room_name | 
| room_id   | 
| user_id   | first user connected
| user_id2  | second user connected

I’m not making rooms, I’m simply trying to pair users and send them to a room.

Answer 1

Do you mean join the records?

You could do something like:

select * from rooms as r
left outer join users as u on r.user_id=u.id
left outer join users as u2 on r.user_id2=u2.id
where r.id=123

123 = a room id.

EDIT:

Here is a way to update a Rooms record with two random Users

UPDATE rooms
SET 
user_id=(SELECT id FROM users ORDER BY RAND() LIMIT 0,1),
user_id2=(SELECT id FROM users ORDER BY RAND() LIMIT 0,1),
where id=123

I have tested this and it seems to work. This will keep you from having duplicate users:

UPDATE rooms
SET 
user_id=(SELECT u1.id FROM users as u1 ORDER BY RAND() LIMIT 0,1),
user_id2=(SELECT u2.id FROM users as u2 where user_id <> u2.id ORDER BY RAND() LIMIT 0,1)
where id=123