怎么出售，是在出售后向销售表中插入一条记录吗？是的话

create trigger test_insert 
on test.dbo.销售表
for insert
as
    update A
    set A.库存单价=C.库存单价
    from 销售表 as A inner join inserted as B
    on A.产品名称=B.产品名称
    inner join 库存表 as C
    on A.产品名称=C.产品名称;
    
    update A
    set A.库存数量=A.库存数量-B.出货数量,
        A.库存金额=A.库存数量*A.库存单价
    from 库存表 as A inner join inserted as B
    on A.产品名称=B.产品名称
go

------解决方案--------------------

use hell
go

create table table_stock
(
   product_name nchar(20) not null,
   stock_amount int not null,
   stock_price int not null default 'null',
   [sum] as stock_amount*stock_price
   constraint Uni_table_stock unique (product_name,stock_price)
)
go
create table table_sales
(
  product_name nchar(20) not null,
  sales_amount int not null,
  sales_price  int not null,
  stock_price  int null,
  constraint FK_table_sales_stock_price foreign key (product_name,stock_price) references  table_stock(product_name,stock_price)
)
go
create trigger tri_sales
on table_sales
after insert
as  
begin
 update  a  set [a].[stock_price]=[b].[stock_price]  from  table_sales as  a,table_stock as b
 where a.product_name=b.product_name
 update  b  set b.stock_amount-=a.sales_amount from table_sales as a,table_stock as b
 where a.product_name=b.product_name
 end
 go