Re: NULLs: theoretical problems?
Date: Sat, 18 Aug 2007 08:58:57 GMT
"David Portas" <REMOVE_BEFORE_REPLYING_dportas_at_acm.org> wrote in message
> "David Cressey" <cressey73_at_verizon.net> wrote in message
> SELECT DISTINCT i FROM t WHERE x = x;
> The result is clearly wrong if a null means "x is unknown" or "x is out of
> range" and possibly wrong if null means "x does not apply".
> If you admit nulls then you must deal with predicates that reference
> nullable attributes.
Why? Received on Sat Aug 18 2007 - 10:58:57 CEST