Messaging System with PHP/MySQL

Question

Hi I\'m trying to make a messaging system with php and mysql.

The mysql table is simple: id sender receiver text timestamp

I\'m trying to make the messaging some

Answer 1

SELECT messages.* FROM messages, (SELECT MAX(id) as lastid FROM messages 
WHERE receiver = 13 OR sender = 13 
GROUP BY CONCAT(LEAST(receiver,sender),'.',GREATEST(receiver,sender))) as conversations
WHERE id = conversations.lastid
ORDER BY timestamp DESC

what you need is a unique conversation id between the chat-partners. i've simulated this with the subquery, hope this helps