How many more yards in touchdowns did Willis McGahee have compared to Ray Rice?
return Willis McGahee ;return touchdowns of #1 ;return yards of #2 ;return sum of #3 ;return Ray Rice ;return touchdowns of #5 ;return yards of #6 ;return sum of #7 ;return difference of #4 and  #8
['select', 'project', 'project', 'aggregate', 'select', 'project', 'project', 'aggregate', 'arithmetic']