How many more total yards of field goals did Robbie Gould make than Ryan Longwell?
return Robbie Gould ;return Ryan Longwell ;return field goals of #1 ;return field goals of #2 ;return yards of #3 ;return yards of #4 ;return sum of #5 ;return sum of #6 ;return difference of #7 and  #8
['select', 'select', 'project', 'project', 'project', 'project', 'aggregate', 'aggregate', 'arithmetic']