Re: NULLs: theoretical problems?
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Sat, 18 Aug 2007 08:55:49 -0300
Message-ID: <46c6de02$0$4031$9a566e8b_at_news.aliant.net>
>
>
> But if a null means "x is not present" and nothing more, the result is
> clearly right.
Date: Sat, 18 Aug 2007 08:55:49 -0300
Message-ID: <46c6de02$0$4031$9a566e8b_at_news.aliant.net>
> "David Portas" <REMOVE_BEFORE_REPLYING_dportas_at_acm.org> wrote in message
> news:l_Cdnbfs5KQfllvbRVnytgA_at_giganews.com...
>
>>"David Cressey" <cressey73_at_verizon.net> wrote in message >>news:UGmxi.11$dz3.4_at_trndny01...
>
>>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".
>
> But if a null means "x is not present" and nothing more, the result is
> clearly right.
I disagree completely. The fact than anyone can disagree makes it anything but clear. Received on Sat Aug 18 2007 - 13:55:49 CEST