less { hop { filter_eq { all_rows ; designation hd ; hd 178428 } ; arrival date } ; hop { filter_eq { all_rows ; designation hd ; hd 186408 } ; arrival date } } = true
select the rows whose designation hd record fuzzily matches to hd 178428 . take the arrival date record of this row . select the rows whose designation hd record fuzzily matches to hd 186408 . take the arrival date record of this row . the first record is less than the second record .