Re: weird results from trivial SELECT statement

From my knowledge, I think that NULL is not a value, it's rather the absense
of a value.
It doesn't matter if you use = or !=,  testing 'disabled' against a NULL
column will always fail.

Why dont you try a WHERE clause like
WHERE active != 'disabled
OR active IS NULL
if you want the NULL records as well.

HTH,


Best,
Oliveiros


----- Original Message -----
From: "Lonni J Friedman" <netllama@gmail.com>
To: <pgsql-novice@postgresql.org>
Sent: Wednesday, April 27, 2011 5:25 PM
Subject: [NOVICE] weird results from trivial SELECT statement


> Greetings,
> I've got a Postgresql-8.4.x instance with a bunch of tables taht have
> a text column (called 'active') that can contain any one of the
> following values:
> NULL
> 'disabled'
> <some other text string>
>
> When I run the following query, it seems to ignore NULL values:
> SELECT * FROM mytbl WHERE active!='disabled'
>
> and only returns rows where active!='disabled' AND active IS NOT NULL.
> Is postgresql implicitly assuming that I want non-NULL values?
>
> I can provide additional information, if requested.
>
> thanks!
>
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