sql计算语句

[sjshuang]

A表
在第X行中A.BB=20
在第X+1行中A.dd=20*10
谁会写这个sql语句？

[zanyzyg]

应该能确定行号吧？

update A表
set a.dd=(select a.bb from A表 where id=t.id-1)*10
from A表 t

[wzy_love_sly]

declare @tb table (id int identity(1,1),num1 int,num2 int)
insert into @tb(num1) select 1
insert into @tb(num1) select 2
insert into @tb(num1) select 5
insert into @tb(num1) select 7

update t set num2=(select sum(num1) from @tb where id<=t.id) from @tb t
select * from @tb

id num1 num2
1 1 1
2 2 3
3 5 8
4 7 15

[zanyzyg]

应该能确定行号吧？

update A表
set dd=isnull((select a.bb from A表 where id=t.id-1)*10,dd)
from A表 t

[Herb2]

是这样?????
update a set bb= 20,dd=20*10

[sjshuang]

行号只能知道是上一行，具体的那行就不知道了

[swot2008]

declare curupdate cursor static for
select id from A
fetch next from curupdate into @id
open curupdate
	select @bb = isnull(bb,0) from A where id = (select max(id) as id from A where id < @id)
	update A set dd = @bb*10 where id = @id
	fetch next from curupdate into @id
close curupdate
deallocate curupdate

[skyzcl]

select id= identity(int,1,1),* into # from a

update # set bb=20 where id=X
update # set dd=20*10 where id=X+1

[sjshuang]

X
是未知数

[pt1314917]

什么意思？