Select count of rows in another table in a Postgres SELECT statement

Question

I don\'t know quite how to phrase this so please help me with the title as well. :)

I have two tables. Let\'s call them A and B. The

Answer 1

To answer my own question:

SELECT a.id, a.other_column, ..., 
(SELECT COUNT(*) FROM b where b.a_id = a.id) AS b_count
FROM a;