I have a system that logs radio frequencies.

For each frequency (record) has 4 calculated fields

I need to compare each frequency in the database all other frequencies and all calculations.

The comparison would check ±20 to see if any of the other freqs (or calculations) are in range of each other.

How best to achieve this?

Many thanks

For each frequency (record) has 4 calculated fields

You are a bit thrifty with the details here, descripe the purpose of these!

But basicly should you use the recorded frequency as the indexed side of a selfjoin using the fields value to calculate the upper and lower range, which then should act as a stacked relations defintion using < and ≥ ...

This will provide you with a portalized view of other records within the range, for each record ... including the record it self.

Now further stacking in the relations def. could a non equal with the autoentered recordID, will get rid of the record it self in the portal.

--sd