Re: AW: AW: Re: [SQL] behavior of ' = NULL' vs. MySQL vs. S tand ards

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От Sergio Bruder
Тема Re: AW: AW: Re: [SQL] behavior of ' = NULL' vs. MySQL vs. S tand ards
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Msg-id 20010607095750.C2185@conectiva.com.br
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Ответ на Re: AW: AW: Re: [SQL] behavior of ' = NULL' vs. MySQL vs. S tand ards  (Tom Ivar Helbekkmo <tih@kpnQwest.no>)
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On Thu, Jun 07, 2001 at 02:46:50PM +0200, Tom Ivar Helbekkmo wrote:
> Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at> writes:
> 
> > Thus it could be, that NULL in "where column = NULL" is not defined 
> > to have a special meaning according to SQL92.
> 
> The way I interpret Celko's interpretation of SQL92, that specific
> construct has a meaning; it evaluates to UNKNOWN, thus not to TRUE,
> and the WHERE clause becomes useless, as does any other combination of
> a theta operator and the explicit constant 'NULL'.  This is almost,
> but not quite, an argument for allowing "= NULL" for "IS NULL".  ;-)
> 
> Does anyone out there have the actual text of the standard?
> 
> -tih

I dont know the standard for that, but to add an experience in another
server (Interbase), '= null' has no meaning in Interbase, ie, doesnt
works as 'IS NULL'.

Sergio Bruder

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