How many more people living in San Juan were whites of non-Hispanic origin compared to blacks of non-Hispanic origin?
return people living in  San Juan ;return #1 that were whites of non-Hispanic origin ;return #1 that were blacks of non-Hispanic origin ;return number of  #2 ;return number of  #3 ;return the  difference of #4 and  #5
['select', 'filter', 'filter', 'aggregate', 'aggregate', 'arithmetic']