How many more people are there 60 and over than there are 19 and under?
return people ;return #1 that are 60 and  over ;return #1 that are 19 and  under ;return number of  #2 ;return number of  #3 ;return difference of #4 and  #5
['select', 'filter', 'filter', 'aggregate', 'aggregate', 'arithmetic']