Re: Documentation discrepancy UNIQUE NULLS NOT DISTINCT

On Thu, Jan 19, 2023 at 3:41 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> From here:
>
> https://www.postgresql.org/about/featurematrix/detail/392/
>
> UNIQUE NULLS NOT DISTINCT
>
> By default, NULL values are not treated as distinct entries. Specifying
> NULLS NOT DISTINCT on unique indexes / constraints will cause NULL
> values to be treated distinctly.
>
>
> From here:
>
> https://www.postgresql.org/docs/current/sql-createindex.html
>
> NULLS DISTINCT
> NULLS NOT DISTINCT
>
> Specifies whether for a unique index, null values should be
> considered distinct (not equal). The default is that they are distinct,
> so that a unique index could contain multiple null values in a column.
>
> and here:
>
> https://www.postgresql.org/docs/current/sql-createtable.html
>
> For the purpose of a unique constraint, null values are not considered
> equal, unless NULLS NOT DISTINCT is specified.
>
>
I think saying that NULLs are distinct by default is the better way to
present this. The documentation disagrees on the verbiage but both state
the same truth; the feature matrix page needs to be fixed.

David J.