Message-ID: <3F1D8763.4BE6DCD7@nsd.ca>
Date: Tue, 22 Jul 2003 14:50:11 -0400
From: Jean-Luc Lachance <jllachan@nsd.ca>
MIME-Version: 1.0
To: Stephan Szabo <sszabo@megazone.bigpanda.com>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>, Tom Lane <tgl@sss.pgh.pa.us>,
	"Michael S. Tibbetts" <mtibbetts@head-cfa.cfa.harvard.edu>,
	pgsql-sql@postgresql.org
Subject: Re: min() and NaN
References: <20030722112906.M39399-100000@megazone.bigpanda.com>
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Hey! here is a (stupid maybe) idea.  Why not disallow 'NaN' for a float?

JLL


Stephan Szabo wrote:
> 
> On Tue, 22 Jul 2003, Bruce Momjian wrote:
> 
> > Well, my 2 cents is that though we consider NULL when ordering via ORDER
> > BY, we ignore it in MAX because it really isn't a value, and NaN seems
> > to be similar to NULL.
> >
> > When doing ORDER BY, we have to put the NULL value somewhere, so we put
> > it at the end, but with aggregates, we aren't required to put the NULL
> > somewhere, so we ignore it.  Should that be the same for NaN?  I just
> > don't see how we can arbitrarly say it is greater/less than other
> > values.
> 
> But we already do. When doing a less than/greater than comparison, 'NaN'
> is considered greater than normal values which is different from NULL
> which returns unknown for both.