There's a good run down of NULL's at
http://techdocs.postgresql.org/guides/BriefGuideToNulls
Robert Treat
On Tue, 2003-04-08 at 15:48, P G wrote:
> Also, the "unique predicate" only explains what it
> means to be unique, but it says nothing about how null
> values are treated. Will someone explain what the
> value of null is?
>