我是这么弄的,select b.buyer_uid c1,
round(sum(a.stock_sales_amnt),0) c3,
round((sum(a.stock_sales_amnt)-sum(a.stock_sales_amnt/a.sell_pr*a.old_nn_buy_price))/sum(a.stock_sales_amnt)*100,2) || '%' c2,
 round(sum(a.stock_sales_amnt)/t1.amount,4)*100 ||'%' c4
from buyer b,article a tax t,
(select decode(sum(stock_sales_amnt),0,0.01,sum(stock_sales_amnt)) amount from article) t1
where a.buyer_uid=b.buyer_no
and t.vat_no=a.vat_no
group by b.buyer_uid