RE: SQL to only check for existence:

Check out the EXISTS predicate.

Select 1
>From sysibm/sysdummy1
Where exists (select 1 from my where myfield like '___abc___')

HTH,


Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
  

> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx 
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of rick baird
> Sent: Tuesday, April 18, 2006 10:56 AM
> To: Midrange Systems Technical Discussion; RPG programming on 
> the AS400 / iSeries
> 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
> 
> -- 
> This is the RPG programming on the AS400 / iSeries (RPG400-L) 
> mailing list
> To post a message email: RPG400-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
> or email: RPG400-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/rpg400-l.
> 
>