From: SPAMBLOCK.Maxwell_Smart@ThePentagon.com.SPAMBLOCK (Brian Tkatch)
Newsgroups: comp.databases.oracle.misc
Subject: Re: '' IS NULL?
Date: Tue, 12 Dec 2000 16:44:35 GMT
Organization: Altopia Corp. - Usenet Access - http://www.altopia.com
Lines: 43
Message-ID: <3a3655ed.1872567125@news.alt.net>
References: <3a33b0ec.1699254234@news.alt.net> <AoSY5.42261$Y6.9487544@news1.mntp1.il.home.com> <3a341979.1726019453@news.alt.net> <s7f83t8i55timscus5c9p65u9bub71msp2@4ax.com> <3a344e06.1739472250@news.alt.net> <e$yofK0YAHA.324@net025s> <3a34d921.1775083046@news.alt.net> <Om5FOX4YAHA.291@net025s>
X-Newsreader: Forte Free Agent 1.11/32.235


On Mon, 11 Dec 2000 16:22:23 +0100, "R. Dickhout"
<Reinier_Dickhout@hetnet.nl> wrote:

>
>Brian Tkatch <SPAMBLOCK.Maxwell_Smart@ThePentagon.com.SPAMBLOCK> wrote >
>>They ARE the same thing. Oracle explicitly states that '' is NULL.
>> >
>> >Reinier.
>> >
>> Hmm.. Missed that then. I'll keep an eye out for that in the docs.
>> Thanx.
>>
>> Brian
>>
>Just for your information, the following text comes from the PL/SQL user
>guide and reference version 8.0:
>
>Zero-Length Strings
>
>
>PL/SQL treats any zero-length string like a null. This includes values
>returned by character functions
>and Boolean expressions. For example, the following statements assign nulls
>to the target variables:
>
>null_string := TO_VARCHAR2('');
>zip_code := SUBSTR(address, 25, 0);
>valid := (name != '');
>
>
>So, use the IS NULL operator to test for null strings, as follows:
>
>IF my_string IS NULL THEN ...
>
>
>Regards,
>
>Reinier.
>
>
Thanx.

Brian