How many more home runs did Mike Coolbaugh have compared to D.J. Boston?
return Mike Coolbaugh ;return D.J Boston ;return home runs of #1 ;return home runs of #2 ;return the  number of  #3 ;return the  number of  #4 ;return the  difference of #5 and  #6
['select', 'select', 'project', 'project', 'aggregate', 'aggregate', 'arithmetic']