and { only { filter_eq { all_rows ; weeks on top ; 11 } } ; eq { hop { filter_eq { all_rows ; weeks on top ; 11 } ; song } ; mambo no 5 } } = true
select the rows whose weeks on top record is equal to 11 . there is only one such row in the table . the song record of this unqiue row is mambo no 5 .