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12 rows affected
| name | category | total_number_of_rows | year_when_var1_changed | var1_before | var1_after | var2_before | var2_after |
|---|---|---|---|---|---|---|---|
| Alice | Var1 Changed | 3 | 2003 | b | b | b | b |
| Bob | Var1 Changed | 1 | 2001 | null | b | null | b |
| John | Var1 Changed | 1 | 2001 | null | a | null | a |
| Mary | Var1 Changed | 3 | 2003 | b | b | b | b |
| Bob | Var1 Never Changed | 2 | null | b | b | b | a |
| John | Var1 Never Changed | 2 | null | a | a | b | b |
Warning: Null value is eliminated by an aggregate or other SET operation.