Get last Message Reply From Conversation - mysql

Question

so I have two tables chats and chats_reply. The structure is the following.
chats
--------------------------------------------------
| chat_id | user_one | user_two | created_at
--------------------------------------------------
| 1 | 1 | 2 | something here
--------------------------------------------------
chats_reply
-------------------------------------------------------------------------
| chatReply_id | chat_id | user_id | reply | created_at
-------------------------------------------------------------------------
| 1 | 1 | 1 | Message 1 | something here
-------------------------------------------------------------------------
| 2 | 1 | 2 | Message 2 | something here
-------------------------------------------------------------------------
I'm having a bit of a problem with my query. Let's say my user_id is 1. I want to return a list of all my chats with the last message that was sent. I already have the query that lists all my chats, but it doesn't return the last message it return the first message of the conversation. This is my query:
SELECT
chats.chat_id,
chats.created_at AS ChatTime,
chats_reply.reply,
chats_reply.created_at AS ReplyTime,
chats_reply.status,
users.name,
users.last_name,
users.email
FROM chats
INNER JOIN chats_reply
ON chats.chat_id = chats_reply.chat_id
INNER JOIN users
ON users.user_id =
CASE
WHEN chats.user_one = '1'
THEN chats.user_two
WHEN chats.user_two = '1'
THEN chats.user_one
END
WHERE chats.user_one = '1' OR chats.user_two = '1'
GROUP BY chats_reply.chat_id
ORDER BY chats_reply.chatReply_id DESC
This query returns everything I'd expect, the problem is it return Message 1 from the chats_reply table when I want it to return Message 2. Any help is greatly appreciated.

Answer 1

Use WHERE for filtering. Not GROUP BY:
SELECT c.chat_id, c.created_at AS ChatTime,
cr.reply, cr.created_at AS ReplyTime, cr.status,
u.name, u.last_name, u.email
FROM chats c INNER JOIN
chats_reply cr
ON c.chat_id = cr.chat_id INNER JOIN
users u
ON (u.user_id = c.user_two AND c.user_one = 1) OR
(u.user_id = c.user_one AND c.user_two = 1)
WHERE 1 IN (c.user_one, c.user_two) AND
cr.chatReply_id = (SELECT MAX(cr2.chatReply_id)
FROM chat_reply cr2
WHERE cr2.chat_id = cr.chat_id
);