If one stairway railing is made of four horizontal ropes.
return stairway ;return railing of #1 ;return ropes ;return #3 that are horizontal ;return the  number of  #4 for each  #2 ;return #2 where  #5 is equal to  four ;return the  number of  of #6 ;return if  #7 is equal to  one
['select', 'project', 'select', 'filter', 'group', 'comparative', 'aggregate', 'boolean']