SQL - How To Order Using Count From Another Table

Question

1. Bloggers

blogger_id
1 
2
3

2. Posts

post_from_blogger_id
1 
1
1
2
2
3

As

Answer 1

Use subqueries.

select * from (
    select post_from_blogger_id, count(1) N from Posts
    group by post_from_blogger_id) t
order by N desc