For a single row fetch ... RPG may be still faster, simply from the point No Optimization (RPG) versus at least one FULL Optimization (and subsequent PSEUDO Opens) in SQL.
May be if SQL can perform an Index Only Access SQL could be as fast or even faster than RPG.
... and there are also differences in SQL:
SELECT MAX(Col)
from ....
Where ...
(could be slower than)
SELECT Col
From ...
Where
Order By Col Desc
Limit 1;
In either way there should be an index over the Columns in the WHERE condition with = and the Column which maximum has to be determined.
... but you have to test it.
Mit freundlichen Grüßen / Best regards
Birgitta Hauser
"Shoot for the moon, even if you miss, you'll land among the stars." (Les Brown)
"If you think education is expensive, try ignorance." (Derek Bok)
"What is worse than training your staff and losing them? Not training them and keeping them!"
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-----Original Message-----
From: RPG400-L <rpg400-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Alan Cassidy
Sent: Dienstag, 9. November 2021 19:49
To: rpg400-l@xxxxxxxxxxxxxxxxxx
Subject: Select into versus SETGT and READPE or READP
i'm using SQL to get the maximum value for a field meeting key field WHERE comparisons into an RPG variable.
I'm replacing code that used the SETGT with READPE to find the maximum value.
I'm wondering which method shows better performance if somebody knows. I was told once that single-value CHAIN trumps using SQL to get one value for one composite key. But time has passed and IBM keeps on juicing up the SQL engine...
-Alan Cassidy
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