题目：删除“客户”表数据时引发的DELETE触发器。
当删除某条客户信息时，同时删除“订单”表中该客户的所有订单。
go
if exists(select name  from sysobjects
      where name='delete_kehu'and type='tr')
    drop trigger delete_kehu
go
create trigger delete_kehu on 客户
for delete
as
if exists(select *
    from deleted
    where 订单.客户id=deleted.客户id)
begin
 delete 订单  
  from 订单,deleted
  where 订单.客户id=deleted.客户id
end