Message-ID: <3B1F848C.CAA0F438@fourpalms.org>
Date: Thu, 07 Jun 2001 13:41:32 +0000
From: Thomas Lockhart <lockhart@fourpalms.org>
Reply-To: lockhart@fourpalms.org
Organization: Yes
MIME-Version: 1.0
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Stephan Szabo <sszabo@megazone23.bigpanda.com>,
	Mark Stosberg <mark@summersault.com>, pgsql-sql@postgresql.org,
	pgsql-hackers@postgresql.org
Subject: Re: behavior of ' = NULL' vs. MySQL vs. Standards
References: <Pine.BSF.4.21.0106061809050.18346-100000@megazone23.bigpanda.com>
	<6689.991880382@sss.pgh.pa.us>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

> > Yes, column = NULL should *never* return true according to the spec (it
> > should always return NULL in fact as stated).  The reason for breaking
> > with the spec is AFAIK to work with broken microsoft clients that seem to
> > think that =NULL is a meaningful test and generate queries using that.
> Microsoft Access is the guilty party, IIRC.  I recently tried to stir up
> some interest in changing this behavior back to the standard, but
> apparently there are still too many people using broken versions of
> Access.

Since according to the standard "column = NULL" is a near-useless
construct (equivalent to "FALSE") it does not seem to pollute the
grammar much to allow an M$ compatible interpretation. I was not happy
having it added (much better to ask that responsive, customer-focused
company to fix their language compliance) but now that it is there it
seems to be an isolated and manageable feature.

                      - Thomas