>>Steve,
>>
>>Tore already gave you the answer. I'd also add that write the expression like you'd see in an algebra text ( 10 < a < 15 ) in a SQL statement won't fully optimize:
>>
>>

>>select sum(b) ;
>>   from x ;
>>   where 10 < a and a < 15
>>

>>
>>10 < a won't optimize because the field is on the right hand side of the operator. a > 10 will optimize.
>
>Thanks for reminding me... would you know whether a " a Between 10.01 and 14.99" would optimize?

Yes it will!