David,
First, if you haven't already, check out the midrange-l archive. There are numerous discussions about SQL performance there that may help.
INMO, and not a direct answer to your question, I wouldn't use SQL in the way you have shown in this and your other post. These functions are quite easily, and probably more efficiently, done using RPG functionality. I am a big fan of using SQL when selecting groups of records for a program. Just not to replicate RPG functions in RPG programs.
Remember that SQL is set based not record based.
HTH,
Rick
-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of David FOXWELL
Sent: Thursday, December 18, 2008 8:26 AM
To: RPG programming on the IBM i / System i
Subject: SQL performance question 2
My second question :
I'm rather worried when I see this :
EXEC SQL
Select MAX (keyfield2) Into : wkeyfield2
From Myfile
Where keyfield1 = : wKeyfield1;
To replace this :
SETGT (wKeyfield1 :wKeyfield2 ) MyFile
READP MyFile
To get the highest value of wKeyField2 for wKeyField1.
I would have thought that, on a large file, RPG would excel here.
I'd like your opinion.
--
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