Question

I have a table in my Oracle DB with data stored such as

ROLE_ID | USER_ID
------------------
 14     | USER A
 15     | USER A
 11     | USER B
 13     | USER A
 15     | USER B
 12     | USER C
 15     | USER C

I want to get all the USER_IDs which have ROLE_ID of both 13 and 15. Based on the example above, I should only get back USER_A.

If I write the query below

select * from table where ROLE_ID in (13,15); then I get other users as well.

How can I modify the query so that I only get back USER A

Answer 1

You’re looking for having…

select user_id
  from my_table
 where role_id in (13,15)
 group by user_id.
having count(distinct role_id) = 2

You ensure, by using the distinct, that if there is say two USER A’s that you still get one where it has both role_ids