From: SPAMBLOCK.Maxwell_Smart@ThePentagon.com.SPAMBLOCK (Brian Tkatch)
Newsgroups: comp.databases.oracle.server
Subject: Re: select blabla where xy = null (8i)
Date: Wed, 08 Aug 2001 16:41:47 GMT
Organization: Altopia Corp. - Usenet Access - http://www.altopia.com
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On Wed, 8 Aug 2001 18:06:51 +0200, "Peter Jenny"
<peter.jenny@cedes.com> wrote:

>Hello
>
>why is this sql-statement not working ?
>select count(*) from anlage where pr_Anleitung = null
>I know I've got entries with null, but the result is: 0
>
>And why does
>select count(*) from anlage where pr_Anleitung <> 'Y'
>not select the entries with pr_Anleitung  = null ?
>
>Thanks Peter
>
>

NULL does not mean nothing. It means UNKNOWN. Oracle, therefore, does
not know if the value equals Y or not, and thus ignores the record.

Any comparison with NULL results in NULL. An unworkable value. To deal
with NULLs, there is the IS NULL keywords.

Brian