Re: AW: AW: Re: [SQL] behavior of ' = NULL' vs. MySQL vs. S tand ards - Mailing list pgsql-hackers

From Tom Ivar Helbekkmo
Subject Re: AW: AW: Re: [SQL] behavior of ' = NULL' vs. MySQL vs. S tand ards
Date
Msg-id 86snhcpidh.fsf@athene.i.eunet.no
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In response to AW: AW: Re: [SQL] behavior of ' = NULL' vs. MySQL vs. S tand ards  (Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at>)
Responses Re: AW: AW: Re: [SQL] behavior of ' = NULL' vs. MySQL vs. S tand ards  (Sergio Bruder <bruder@conectiva.com.br>)
List pgsql-hackers
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
-- 
The basic difference is this: hackers build things, crackers break them.


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