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Hi Fred -

Could this be the difference:

Index size . . . . . . . . . . . . . . : 1056768

vs:

Index size . . . . . . . . . . . . . . : 24576

You can't just change S to O and reverse the comparison to get the equivalent.


The one logical is including records where PSATFG = 'A' *OR* PSSTCD < '30'
the other is including records where PSATFG = 'A' *AND* PSSTCD < '30'

If the selections are actually equivalent, the use of S vs O makes no difference. I don't remember where I saw it, but internally the omits are converted to selects anyway.

Ordering is another matter (and another opportunity to create a logical that isn't actually equivalent if you have a mixture of S/O or and/or). This is only going to matter when adding/changing records. Performance will benefit, albeit probably not very much, by listing the most exclusive (in terms of the number of records) comparison first.

--
Ken
http://www.ke9nr.net/
Opinions expressed are my own and do not necessarily represent the views of my employer or anyone in their right mind.



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