Re:RE: comparing null values

Sony and Gary,

    Null is a "special" condition of data. A data point cannot equal or not equal null, therefore 'like' and 'not like' also does not work as neither is true. Therefore SQL recognizes 'null' and 'not null' for the purpose of evaluating nulls. Consider the null state as being the complete non existence of the data point only. That being said, then a null neither exists nor does not exist. It's just NULL.

    An instructor put the logic of Nulls this way: In logic things are either TRUE, FALSE, or NULL.

Dick Goulet

____________________Reply Separator____________________
Author: Sony kristanto <Sony_at_polyfincanggih.com>
Date:       1/30/2003 6:22 PM

Hi Gary,

I wonder why you didn't use :
select * from tester2 where whatever is null;

Null values is extremely empty.

Rgrds,

Sony

> -----Original Message-----
> From: Gary Jackson [SMTP:fred_fred_1_at_hotmail.com]
> Sent: Friday, January 31, 2003 12:42 AM
> To: Multiple recipients of list ORACLE-L
> Subject: comparing null values
>
> Can anyone explain why it is that I seem unable to use 'like' and 'not
> like'
> on columns containing null values. (I am unable to find information
> regarding this on MetaLink.)
>
> For example:
>
> SQL> select * from tester2;
>
> COL1 COL2 WHATEVER
> ---- ---- --------
> 1 1 STUFF
> 2 2 STUFF
> 3 3
> 4 4
>
> SQL> select * from tester2 where whatever not like '%STU%';
> no rows selected
>
>
> My question is why does this not return the 3 & 4 columns?
>
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-- 
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-- 
Author: Sony kristanto
  INET: Sony_at_polyfincanggih.com

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  INET: dgoulet_at_vicr.com

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