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Re: behavior of ' = NULL' vs. MySQL vs. Standards

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com>
Cc: Mark Stosberg <mark(at)summersault(dot)com>, pgsql-sql(at)postgresql(dot)org, pgsql-hackers(at)postgresql(dot)org
Subject: Re: behavior of ' = NULL' vs. MySQL vs. Standards
Date: 2001-06-07 02:19:42
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackerspgsql-sql
Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> writes:
> 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

A compromise answer might be to offer a SET variable that selects the
Microsoft-compatible misimplementation.  Would that fly?

			regards, tom lane

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