Question

I need to add a join to the following query that will join the messages_message table to the messages_threads table and return the ‘body’ and ‘time’ fields from the most recent row in messages_messages where messages_message.threadid = messages_threads.id.

Sorry that’s so confusing, I don’t know how else to phrase it! Here’s my current query – which pulls everything correctly except the ‘body’ and ‘time’ fields.

SELECT 
    messages_threads.id AS threadid, messages_threads.name AS recipientsname, 
    senderid, username AS sendername, pictures.url AS senderpicture
FROM 
    messages_recipients
    JOIN messages_threads 
        ON messages_threads.id = messages_recipients.threadid
    JOIN users 
        ON users.id = messages_threads.senderid
    JOIN pictures 
        ON messages_threads.senderid = pictures.userid 
        AND pictures.profile = 1
WHERE messages_recipients.userid = $userid

Answer 1

You could add a subquery of the messages_message table which would return 1 row for every thread. For example:

SELECT 
    messages_threads.id AS threadid, messages_threads.name AS recipientsname, 
    senderid, username AS sendername, pictures.url AS senderpicture
FROM 
    messages_recipients
    JOIN messages_threads ON messages_threads.id = messages_recipients.threadid
    JOIN users ON users.id = messages_threads.senderid
    JOIN pictures ON messages_threads.senderid = pictures.userid AND pictures.profile = 1
    JOIN ( SELECT threadid, MAX(id) AS postid FROM messages_message GROUP BY threadid ) t ON message_threads.id = t.threadid
    JOIN messages_message ON t.threadid = messages_message.threadid AND t.postid = messages_message.id
WHERE messages_recipients.userid = $userid