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| id | col1 | col2 | What I want | What you get |
|---|---|---|---|---|
| 1 | x | a | 1 | 1 |
| 2 | x | b | 2 | 2 |
| 3 | x | a | 3 | 3 |
| 4 | x | a | 3 | 3 |
| 5 | x | c | 4 | 4 |
| 6 | x | c | 4 | 4 |
| 7 | x | c | 4 | 4 |
Warning: Null value is eliminated by an aggregate or other SET operation.