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Michael,

Go to iNav, SQL Scripts. Write a prototype of your statement, just the
SELECT part, and run it with VE (only the explain part). VE's advisor would
show you (if needed) a recommendation for any required indexes.

HTH,

Luis Rodriguez
IBM Certified Systems Expert — eServer i5 iSeries
--



On Wed, Mar 23, 2011 at 3:46 PM, Michael Ryan <michaelrtr@xxxxxxxxx> wrote:

Well, here's another. I have an SQL statement that looks like this:

C/Exec SQL
C+ DECLARE C1 CURSOR FOR
C+ Select * From MYFILE
C+ Where Imfld1 Between :HostFld1 and :HostFld2
C+ And Imfld2 Between :HostFld3 and :HostFld4
C+ And Imfld3 Between :HostFld15 and :HostFld16
C+ And Imfld4 Between :HostFld17 and :HostFld18
C+ Order By Case When :DspSort = 1 Then Imfld1 Else NULL End,
C+ Case When :DspSort = 1 Then Imfld2 Else NULL End
C+ For Read Only
C/End-Exec

This is a simple example - some are more complex (as in more
comparisons). Using the Between clause is great with high and low
values, but it can be very slow. How do I attack a problem like this?
How do I know what indexes or views or whatever to make? Do I even
want to do that? I know this is incomplete information, but I have to
start somewhere.

Cross posted since it's RPG but it's SQL in nature.

Thanks!
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