How to find owners who own more than one apartment in the same building?

Question

SQL

Is there a table on how to find owners who own more than one apartment in the same building?
id|flat_num|house_id|owner_id|
1|12 |2 |1 |
2|22 |3 |3 |
3|10 |3 |3 |
4|30 |1 |2 |
5|12 |2 |4 |
6|22 |3 |4 |

Answer 1

SELECT owner_id FROM t1
GROUP BY owner_id, house_id 
HAVING count(owner_id, house_id) > 1;

Answer 2

poke