greater { hop { filter_eq { all_rows ; callsign ; xemr } ; frequency } ; hop { filter_eq { all_rows ; callsign ; xeg } ; frequency } } = true
select the rows whose callsign record fuzzily matches to xemr . take the frequency record of this row . select the rows whose callsign record fuzzily matches to xeg . take the frequency record of this row . the first record is greater than the second record .