Re: "= null" & "is null"

From: Ed Prochak <prochak_at_my-deja.com>
Date: Fri, 03 Sep 1999 17:22:38 GMT
Message-ID: <7qp04g$ndo$1@nnrp1.deja.com>

In article <7qo5sc$187m$2_at_adenine.netfront.net>, Norris <johnnie_at_cooper.com.hk> wrote:
>
>
> Niall Litchfield <n-litchfield_at_audit-commission.gov.uk> wrote:
> > Norris <johnnie_at_cooper.com.hk> wrote in message
> > news:7qat7c$rvt$1_at_adenine.netfront.net...
> >> Maybe I need to change my question to the difference between "<>
null"
> >> and "is not null".
>
> > "<> Null" Is still a meaningless statement. Is Not Null means there
is a
> > known value. <> Null would mean is not equal to an unknown value.
>
> "<> Null" is a meaningless statement? So, in any cases, we should
never use it, am I right?
>
> --
> Have several nice days...
>

Right! Now you are catching on!!

expression     possible resulting values
X IS NULL          TRUE  FALSE
X IS NOT NULL      TRUE  FALSE
X = NULL           UNKNOWN
X <> NULL          UNKNOWN

You ended the week on a positive note.
Have a good weekend.

--
Ed Prochak
Magic Interface, Ltd.
ORACLE services
440-498-3700 <<<NOTE new number

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Share what you know. Learn what you don't. Received on Fri Sep 03 1999 - 12:22:38 CDT