Mine

		SELECT			t.id AS thread_id,			t.headline AS thread_headline,			t.posted_at AS thread_posted_at,			r.posted_at AS last_reply_posted_at,			r.id AS last_reply_id,			(SELECT COUNT(*) FROM replies WHERE thread_id = t.id) AS num_replies		FROM threads AS t		JOIN replies AS r ON t.id = r.thread_id                where not exists (select 1                                    from replies r1                                   where r1.thread_id = t.id                                     and r1.posted_at < r.posted_at)		ORDER BY			thread_posted_at DESC,			last_reply_posted_at DESC		LIMIT 10