greater { hop { filter_eq { all_rows ; aircraft ; bell 212 } ; in service } ; hop { filter_eq { all_rows ; aircraft ; bell 412 } ; in service } } = true
select the rows whose aircraft record fuzzily matches to bell 212 . take the in service record of this row . select the rows whose aircraft record fuzzily matches to bell 412 . take the in service record of this row . the first record is greater than the second record .