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| employee_id | department_id | primary_flag |
|---|---|---|
| 1 | 1 | N |
| 2 | 1 | Y |
| 2 | 2 | N |
| 3 | 3 | N |
| 4 | 2 | N |
| 4 | 3 | Y |
| 4 | 4 | N |
| employee_id | department_id |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 3 |
Warning: Null value is eliminated by an aggregate or other SET operation.