Is this the most efficient way to write this query? Id like to get a list of users that have the categories 1, 2, and 3? SELECT user_id FROM user_categories WHERE category_id IN (1,2,3) GROUP BY user_id HAVING COUNT(*) = 3 users_categories (user_id, category_id) 1 | 1 1 | 2 1 | 3 2 | 1 2 | 2 3 | 1 4 | 1 4 | 2 4 | 3 The result should produce 1 & 4. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
