Grab only the last post from all topics in a category from phpbb

Question

Hello,

I want to only grab the last post of all topics in a category (Category->Forum->Topic->Post) from a phpbb database in a single query. Currently I have cooked up this, but it returns only the first post, not the last.

SELECT *, MAX(p.post_id)
FROM phpbb_forums f, phpbb_topics t, phpbb_posts p
WHERE f.parent_id IN (<categories>)
AND t.forum_id = f.forum_id
AND p.topic_id = t.topic_id
GROUP BY p.topic_id

Does anybody know how to correctly do this?

Answer 1

SELECT  *
FROM    phpbb_forums f
JOIN    phpbb_topics t
ON      t.forum_id = f.forum_id
JOIN    phpbb_posts p
ON      p.post_id = 
        (
        SELECT  pi.post_id
        FROM    phpbb_posts pi
        WHERE   pi.topic_id = t.topic_id
        ORDER BY
                pi.date DESC
        LIMIT 1
        )
WHERE   f.parent_id IN (…)