Re: SQL to only check for existence

Hey Rick,

This is the optimum solution I believe.

FOUND = *OFF
SELECT '1' INTO :FOUND
FROM FILE
WHERE FIELD LIKE '___abc___'
FETCH FIRST 1 ROWS ONLY

Mark

> ----- Message from "rick baird" <rick.baird@xxxxxxxxx> on Tue, 18 
> Apr 2006 10:56:16 -0400 -----
> 
> To:
> 
> "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>, 
> "RPG programming on the AS400 / iSeries" <rpg400-l@xxxxxxxxxxxx>
> 
> Subject:
> 
> SQL to only check for existence:
> 
> hey all,
> 
> Is there a way to run an SQL statement that doesn't (necessarily)
> return anything, but only checks for the existence of one or more
> records based on a where statement - similar to a SETLL and %found?
> 
> I've got a rather complicated SQL statement using:
> LIKE '___abc___'    or it could be:
> LIKE ______xyz'
> 
> - over a very large file, and I'm having performance issues.
> 
> I don't want to do a count(), because I don't care how many, only that
> at least one exists.   with count, it would have to read through the
> entire file to determine it.
> 
> I also tried just doing a select - optimize for 1 row and a single
> fetch, but that seemed to take forever too.  It appears as if it is
> searching the entire file, instead of stopping at the first one.
> 
> help!
> 
> Rick