Re: How to improve this query?

From: Sybrand Bakker <gooiditweg_at_sybrandb.nospam.demon.nl>
Date: Mon, 24 Nov 2003 10:33:49 +0100
Message-ID: <21k3svgttf4ujetb51q1g3ugds9q6jj45t@4ax.com>

On Fri, 21 Nov 2003 15:17:22 +0100, "Tom Miskiewicz" <miskiewicz2_at_yahoo.com> wrote:

>Hello!
>
>I want to count those records in a table, where the field I specified is not
>empty. How to make such a query efficient. Is there a different/more
>efficient way to achieve that, then select count(1) from mytable where
>myfield != NULL? Myfield is a varchar2 field. I'm using Oracle 9.
>
>
>Thanks
>Thomas
>

!= NULL won't work. You can't apply equality or inequality to null as NULL doesn't compare to anything. SQL implements three-valued logic: true, false and NULL. You'll need to use IS NOT NULL or > chr(0) provided the column is indexed.

--
Sybrand Bakker, Senior Oracle DBA

Received on Mon Nov 24 2003 - 03:33:49 CST