Re: So what's null then if it's not nothing?
From: Jon Heggland <heggland_at_idi.ntnu.no>
Date: Thu, 1 Dec 2005 09:26:37 +0100
Message-ID: <MPG.1df8d22c6d714983989720_at_news.ntnu.no>
Date: Thu, 1 Dec 2005 09:26:37 +0100
Message-ID: <MPG.1df8d22c6d714983989720_at_news.ntnu.no>
In article <1133400197.315562.163950_at_g14g2000cwa.googlegroups.com>,
boston103_at_hotmail.com says...
> > > No, the argument is not exactly the same. We have stipulated two
> > > independent rules of the game:
> > >
> > > a. two nulls are not distinct; b. two nulls are not equal
> >
> > a. Projection removes all but one of tuples that are not distinct.
> > b. Projection retains tuples so that all are not equal to any other.
> >
>
> You cannot use (b) because the equality is unknown for nulls. (a) is
> you only choice.
Read (b) again and notice the "not" before "equal".
-- JonReceived on Thu Dec 01 2005 - 09:26:37 CET