I'm trying to write a query that extracts the total number of undeleted messages sent to friends. Here is a screenshot of the table structure:

The output I want to achieve is as follows:

id          messages_count
 ---------------------------
 1            4562
 2            7255

Here are the queries I have tried so far:

SELECT u.id, count( CASE WHEN m.is_deleted = false THEN m.is_deleted END ) as messages_count
FROM users u
inner join messages m on u.id = m.to_id
GROUP BY u.id
ORDER BY u.id;