Re: '' IS NULL?

From: <martin_suttrup_at_my-deja.com>
Date: Mon, 11 Dec 2000 07:14:54 GMT
Message-ID: <911utc$n5m$1@nnrp1.deja.com>

Hi,

as Steven Feuerstein stated (in Oracle PL/SQL, p359):

The LENGTH function,in fact,will never return zero; it will always return either NULL or a positive number.....

So you will have a string of zero length if it is NULL (and vice versa).

Martin

In article <3a344e06.1739472250_at_news.alt.net>, SPAMBLOCK.Maxwell_Smart_at_ThePentagon.com.SPAMBLOCK (Brian Tkatch) wrote:
> On Mon, 11 Dec 2000 02:32:59 GMT, Bert Byfield
> <rpitts_at_rochester.rr.com> wrote:
>
> >>>Because a space is considered a character. So if you create a
space in a
> >>>field, it is no longer considered NULL.

> >>Then there is no such thing as a zero-length string? In other words,
a
> >>"known" value of nothing, rather than an "unknown" value.
> >
> >The options are:
> >' ' a space
> >'' a zero-length string
> >(nothing) NULL
> >
>
> ->SELECT * FROM Dual WHERE '' IS NULL;
>
> D
> -
> X
>
> It would seem that they are the same thing.
>
> Brian.
>

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Before you buy. Received on Mon Dec 11 2000 - 01:14:54 CST