How many more wins than losses did the 49ers have in 1984?
return the  49ers ;return wins of #1 ;return #2 in  1984 ;return losses of #1 ;return #4 in  1984 ;return number of  #3 ;return number of  #5 ;return difference of #6 and  #7
['select', 'project', 'filter', 'project', 'filter', 'aggregate', 'aggregate', 'arithmetic']