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

DESC for receive New row's . AND ASC or NOT set, Default is ASC:

   (SELECT * FROM messages WHERE receiver = 13 OR sender = 13 GROUP BY receiver,sender ORDER BY id DESC)

AND SET LIMIT 1 ,1 AFTER ORDER BY
i think you need it
(receiver = 13 AND sender = 'usersender id' ) OR (receiver ='usersender id' AND sender = 13 ) Try it!

Answer 2

UPDAte: I'm not sure if it works perfect:

SELECT * FROM messages 
WHERE receiver = 13
GROUP BY receiver,sender 
ORDER BY timestamp DESC
LIMIT 1

UNION ALL
SELECT * FROM messages 
WHERE sender = 13
GROUP BY receiver,sender 
ORDER BY timestamp DESC
LIMIT 1

to reverse the order:

ORDER BY timestamp DESC

Answer 3

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