Count rows from LEFT JOIN where column is value

Question

I have teams, users, and points tables.

When I call get the teams from the database I need to also calculate the points as a generated column and also the number of users in that team as a new column.

I have this so far but it is returning all users in the member count column, not just the members in that team.

SELECT   ar_teams.*, COALESCE(SUM(ar_points.amount),0) AS points, COUNT(ar_users.team_id) AS members
    FROM     ar_teams
        LEFT JOIN ar_users  ON ar_users.team_id  = ar_teams.id
        LEFT JOIN ar_points ON ar_points.user_id = ar_users.id
    WHERE ar_teams.id = 1 AND ar_users.team_id = 1
    GROUP BY ar_teams.id

The results I am getting:

id    name           name_alt    points    members
1     UK & Ireland   NULL        3076      48

The members count should be 12, at the moment it seems to be counting all people without taking their team into account.

Answer 1

I suspect your problem is the use of count() rather than count(distinct). I think this is what you want:

SELECT ar_teams.*,
       COALESCE(SUM(ar_points.amount), 0) AS points,
       COUNT(distinct ar_users.id) AS members