>>>>The actual implementation of this example involves a much more complicated scenario, but I think this expresses the heart of my question.
>>>>
>>>>Calculate sum(b) for a > 10 and a < 15 to m_sum_b
>>>>
>>>>Will execution be speeded up if a is indexed?
>>>
>>>As other have said if there is an INDEX ON A your code will optimize. You can also use BETWEEN(). Calculate sum(b) FOR BETWEEN(a,10,15) to m_sum_b
>>
>>Hi Mike,
>>
>>a small correction to your suggestion: Calculate sum(b) FOR BETWEEN(a,10.0001,14.9999) to m_sum_b
>
>Quite right. Thanks!

No problem. I have always wanted a fourth parameter to the Between() function, namely a True/False for whether the given values are inclusive or not.