How many more field goals did Dan Carpenter convert than Matt Prater?
return Dan Carpenter ;return Matt Prater ;return field goal converts of #1 ;return field goal converts of #2 ;return number of  #3 ;return number of  #4 ;return the  difference of #5 and  #6
['select', 'select', 'project', 'project', 'aggregate', 'aggregate', 'arithmetic']