Andrea Oracle wrote:
>
> Hi, I got a SQL question (9i on Red Hat), commands
> shown below. The first sql returns 3 rows with value
> 1, so trim(client_company) = '', how come the 2nd sql
> doesn't return anything??
>
> SQL> select decode(trim(client_company), '', 1, ' ',
> 2, null, 3, 4) from cli_clients where
> cli_id in (257, 396, 727);
>
> DECODE(TRIM(CLIENT_COMPANY),'',1,'',2,NULL,3,4)
> -----------------------------------------------
> 1
> 1
> 1
>
> 3 rows selected.
>
> SQL> select count(*) from cli_clients where
> trim(client_company) = '' and cli_id in (257,
> 396, 727);
>
> COUNT(*)
> ---------
> 0
>
> 1 row selected.
>
Because NULLs (and '' is a NULL string) can be DECODEdbut are never
equal to anything.
--
Regards,
Stephane Faroult
Oriole Software
--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Stephane Faroult
INET: sfaroult_at_oriole.com
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Received on Thu Mar 06 2003 - 15:09:04 CST
