I ran a similar statement through the Visual explain option in
iNavigator and found that the select distinct solution is not as optimal
as the Fetch first 1 rows only statement.
Exec sql
Select '1' into :indicator
From MyTable
Fetch First 1 Rows Only;
In both cases it appears the optimizer actually runs a "Fetch First 1
Rows Only", however when Distinct is specified the Optimizer has to add
logic to re-write the statement to match the "Fetch First 1 Rows"
example.
So, while the estimated runtimes were very close, the optimization time
for the Distinct clause was about 1000 to 100000 times more than just
coding the Fetch First 1 Rows Only.
Chris Hiebert
-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Colpaert, Peter
Sent: Tuesday, April 24, 2012 10:51 PM
To: RPG programming on the IBM i / System i
Subject: RE: sqlrpgle question
Exec sql
Select distinct '1' into :indicator
From MyTable;
HTH,
Peter Colpaert
Software Engineer - PLM Development Team Philips Consumer Luminaires
Tel: (+32) 3/459 13 17
Fax: (+32) 3/450 74 33
Address: Industrieterrein Satenrozen 11, 2550 Kontich, Belgium
Email: Peter.Colpaert@xxxxxxxxxxx
-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Dave
Sent: dinsdag 24 april 2012 16:48
To: RPG programming on the IBM i / System i
Subject: sqlrpgle question
Hi,
I want to set the value of an indicator to *on if I find at least one
record matching my search criteria and *off otherwise.
What's the best way?
eg :
indicator = *off;
exec sql
Select '1' into : indicator
from mytable
where ....err.. what goes here? what if there are many rows returned?
Thanks!
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