I have this table:

```

+-----+--------+ 
|col1 |   col2 |
+-----+--------+
|   1 |     12 | 
|   1 |     12 |
|   2 |     13 |
|   4 |     15 | 
|   2 |     13 |
|   3 |     14 |
|   3 |     14 |
|   1 |     12 |
+-----+--------+

```

I'm looking for Total sum of col2 for distinct col1.