How many more Portuguese Knights were killed than Isabellian Knights?
return Portuguese Knights  ;return Isabellian Knights  ;return #1 that were killed ;return #2 that were killed ;return number of  #3 ;return number of  #4 ;return the  difference of #5 and  #6
['select', 'select', 'filter', 'filter', 'aggregate', 'aggregate', 'arithmetic']