【原创】SQL数据累计求和等聚合操作

if Object_id('tb1') is not null Drop table tb1;
go
create table tb1(date int primary key, sale int);
go
insert into tb1(date, sale)
select 1, 20 union all
select 2, 15 union all
select 3, 14 union all 
select 4, 18 union all 
select 5, 30;

select * from tb1;

--方法一，单个聚合
select date, sale, (select sum(sale) from tb1 b where b.date <= a.date) as [sum]
from tb1 a;

--方法二,多个聚合时
select a.date, a.sale, sum(b.sale) as [sum]
from tb1 a
    join tb1 b
    on b.date <= a.date
group by a.date, a.sale;

/*
--查询结果
date        sale        sum
----------- ----------- -----------
1           20          20
2           15          35
3           14          49
4           18          67
5           30          97
*/