Is there a simpler way to achieve this style of user messaging?

Question

I have created a messaging system for users, it allows them to send a message to another user. If it is the first time they have spoken then a new conversation is initiated,

Answer 1

The simpleste way I think for this is:

Tables:

conversation(cid | userId | friendId | last_message_id)
messages(mid | message | userId | read | time | cid)

Then update last_message_id after each message insert by users in particulate conversation.

And then run this simple query. It will give you what you want.

SELECT * FROM conversation c, messages m 
WHERE (c.userId='$uid' OR c.friendId='$uid')
AND c.last_msg_id=m.message_id
ORDER BY created_time DESC

$uid is id of logged in user.

So in actual what this process is doing:

1. Displaying all conversation of logged in user.
2. Referencing last message (so you do not need group by)
3. And last displaying messages in order by desc.