I have a set of duplicate records in a SQL db like so:

```
Id  |   Prop1  |   Prop2
--------------------------
1   |   aaa    |   aaa
2   |   aaa    |   aaa
3   |   bbb    |   bbb
4   |   bbb    |   bbb
5   |   ccc    |   ccc
6   |   ccc    |   ccc

```

I need to select each duplicate, or every second row to update it. Would like to get a select statement returning ids

```
2, 4, 6

```

Is it possible?