count-post-ids.sql

SELECT users.user_id, COUNT(post_id) AS post_count
FROM users
LEFT JOIN posts ON posts.user_id = users.user_id
GROUP BY 1

+---------+------------+
| user_id | post_count |
+---------+------------+
|       1 |          3 |
|       2 |          2 |
|       3 |          0 |
+---------+------------+

correct one, it's the same case i was trying to resolve. Thanks