and { only { filter_eq { all_rows ; songwriter ( s ) ; wallis willis } } ; eq { hop { filter_eq { all_rows ; songwriter ( s ) ; wallis willis } ; title } ; swing low , sweet chariot } } = true
select the rows whose songwriter  s  record fuzzily matches to wallis willis . there is only one such row in the table . the title record of this unqiue row is swing low , sweet chariot .