|
|
|
|
|
|
by woevdbz
1445 days ago
|
|
|
An example where NULLS DISTINCT might make sense in a constraint is when a table is used to store an analytical cube roll-up (eg output of GROUP BY ROLLUP), where NULL in a dimension column has special meaning (it indicates subtotals). Having multiple rows with the same NULL key could, in some of those cases, be an error leading to double-counting. |
|
|