If one of the bookshelves has decorative items on top as well as on the shelves.
return bookshelves ;return decorative items ;return top of #1 ;return #1 where  #2 are on #3 ;return shelves of #4 ;return #4 where  #2 are on #5 ;return number of  #6 ;return if  #7 is equal to  one
['select', 'select', 'project', 'comparative', 'project', 'comparative', 'aggregate', 'boolean']