eq { diff { hop { filter_eq { all_rows ; race ; german grand prix } ; date } ; hop { filter_eq { all_rows ; race ; british grand prix } ; date } } ; 15 days } = true
select the rows whose race record fuzzily matches to german grand prix . take the date record of this row . select the rows whose race record fuzzily matches to british grand prix . take the date record of this row . the first record is 15 days larger than the second record .