# alex@xxxxxxxxxxxxxxx / 2005-01-20 01:35:32 +1100:
i have a unique index on a table over multiple columns. If now one of the records has a null value in one of the indexed columns i can insert the same record multiple times.
Is this a problem within postgres or expected?
In SQL, NULL means "unknown value". How could you assert that two NULLs are equal?
which doesn't make mathematical sense. mathwise null is an empty result. so setting the logic up using the math logic, null values are always equal.
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