1. Bloggers
blogger_id 1 2 3
2. Posts
post_from_blogger_id 1 1 1 2 2 3
As
SELECT b.* FROM Bloggers AS b LEFT JOIN ( SELECT post_from_blogger_id, COUNT(*) AS post_count FROM Posts GROUP BY post_from_blogger_id ) AS p ON b.blogger_id = p.post_from_blogger_id ORDER BY p.post_count DESC