Question

I’ve a table with some data like this:

|   cod_1   |   cod_2   |
-------------------------
|   1       |   03      |
|   2       |   07      |
|   2       |   09      |
|   3       |   09      |
|   4       |   01      |
|   4       |   02      |
|   4       |   08      |

In this case I need to get the cod_1 2 and 4 because they have more tahn one cod_2 associated.

Answer 1

You can do it like this:

SELECT cod_1
FROM tablename
GROUP BY cod_1
HAVING count(*) > 1