How to check if value exists in each group (after group by)

Question

Assume I have a subscriptions table :

uid  | subscription_type 
------------------------  
Alex | type1
Alex | type2
Alex | type3
Alex | type4
Ben  | type2
B         


        

Answer 1

To check if something doesn't exist, use NOT EXISTS(...):

SELECT uid
FROM subscribes su
WHERE NOT EXISTS (SELECT *
        FROM subscribes nx
        WHERE nx.uid = su.uid AND nx.subscription_type = 'type1'
        )
GROUP BY uid HAVING COUNT(*) > 2
        ;