MySQL order by count of another table

Let's say I have:

   SELECT bloggers.*, 
 开发者_如何学运维         COUNT(post_id) AS post_count
     FROM bloggers 
LEFT JOIN blogger_posts ON bloggers.blogger_id = blogger_posts.blogger_id
 GROUP BY bloggers.blogger_id
 ORDER BY post_count

That returns all bloggers ordered by their post count. What if I want just some bloggers but still ordered by the same criteria (for example those whose AUX field is equal to 3)?

The WHERE clause should come immediately before the GROUP BY clause. When in doubt about something as straightforward as syntax, the place to look is the manual.

MySQL Manual :: SELECT Syntax

   SELECT bloggers.*, 
          COUNT(post_id) AS post_count
     FROM bloggers 
LEFT JOIN blogger_posts ON bloggers.blogger_id = blogger_posts.blogger_id
    WHERE bloggers.AUX = 3
 GROUP BY bloggers.blogger_id
 ORDER BY post_count