比如我现在的结果是（现在是动态列为年份，值是amount）：
2006 2007 2008 2009
amount amount amount amount
3000 5000
可以看出2007和2009的数据为null，那么如果我要2007继承2006的amount数据，即3000；2009继承2008的5000，如何办到？
也就是说如果一年的amount为null，就自动继承前一年的数据。
表可以是静态也可以是动态的，在下是新手，请高手指教。
------解决方案--------------------
//测试数据
create table tb_xx(
company varchar(10) not null ,
amount numeric(10,2) null ,
year numeric(4) not null,
primary key(company,year)
);
insert into tb_xx(company,amount,year)
SELECT 'COMPANY A',3000,2006
union
SELECT 'COMPANY A',5000,2008
union
SELECT 'COMPANY B',2000,2007
union
SELECT 'COMPANY B',8000,2009;
//呵呵，查询的SQL
select c.company,b.year,amount=(select top 1 amount from tb_xx where company=c.company and year<=b.year order by year desc)
from tb_xx a,(select distinct year from tb_xx) b,(select distinct company from tb_xx)c
where a.year=*b.year and a.company=*c.company
order by c.company,b.year