Reputation: 17918
I am writing a subscription cleanup query that should select all canceled subscriptions, whose users don't have any other active subscription (the application allows multiple subscriptions per user).
I started with this:
SELECT * FROM subscriptions s WHERE status = 'canceled' AND (SELECT COUNT(*) FROM subscriptions s2 where s2.user_id = s.user_id AND status = 'active') = 0;
However, I feel there must be an easier/more straightforward/more performant way.
Upvotes: 0
Views: 934
Reputation: 693
NOT EXISTS can be more intuitive here:
SELECT * FROM subscriptions s WHERE status = 'canceled'
AND NOT EXISTS
(SELECT id FROM subscriptions s2 where s2.user_id = s.user_id AND status = 'active');
You can also use a LEFT JOIN here:
SELECT *
FROM
subscriptions s LEFT OUTER JOIN
subscriptions s2 ON s.USER_ID = s2.USER_ID AND s2.status='active'
WHERE status = 'canceled' AND s2.id IS NULL
Upvotes: 3