Re: Nulls get converted to 0 problem

From: Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com>
To: Jon Earle <je_pgsql(at)kronos(dot)honk(dot)org>
Cc: <pgsql-general(at)postgresql(dot)org>
Subject: Re: Nulls get converted to 0 problem
Date: 2003-06-06 13:32:13
Message-ID: 20030606062746.J26692-100000@megazone23.bigpanda.com
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On Thu, 5 Jun 2003, Jon Earle wrote:

> On Wed, 4 Jun 2003 terry(at)ashtonwoodshomes(dot)com wrote:
>
> > Oracle *incorrectly* interprets blank (empty) strings as NULL. They are NOT
> > the same. A string of zero characters is a string nonetheless. A NULL is
> > "the absence of value", which equals nothing (theoretically not even another
> > NULL).
>
> If you're testing a value, you're testing to see if there's something in
> there or not - what difference does it make if the variable contains 0, ""
> or NULL?
>
> Why not adhere to the practices inherent (and thus anticipated by
> developers) in other languages (C comes to mind) where 0, NULL and "" are
> equivalent?

Because SQL already defines what NULL means to be something else, it's an
unknown value. Also, in C, NULL and "" are different and not very
equivalent (try passing strcmp a NULL rather than empty string on many
systems ;) )

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