greater { hop { filter_eq { all_rows ; date ; 13 may 1998 } ; weight ( kg ) } ; hop { filter_eq { all_rows ; date ; 23 aug 1997 } ; weight ( kg ) } } = true
select the rows whose date record fuzzily matches to 13 may 1998 . take the weight  kg  record of this row . select the rows whose date record fuzzily matches to 23 aug 1997 . take the weight  kg  record of this row . the first record is greater than the second record .