获取上一行金额字段

Question

我有一个表，其中有几列PersonID，Amount和StartDate，并提供了1个人作为示例。我想做的是 自动计算BeforeAmountCalculatedColumn，基本上是从上一行（按日期）开始 数量是。我该怎么办？

Create Table #Results
(
    PersonID int,
    Amount money,
    StartDate datetime,
    BeforeAmountCalculatedColumn money
)

insert into #Results
(
    PersonID,
    Amount,
    StartDate,
    BeforeAmountCalculatedColumn
)
select
    1,
    '163.45',
    '30 Jan 2019',
    '202.70'
union all
select
    1,
    '202.70',
    '23 Nov 2018',
    '189.45'
union all
select
    1,
    '189.45',
    '28 Aug 2018',
    '0'

Answer 1

您要寻找lag()吗？

select r.*,
       lag(amount) over (partition by personid order by startdate) as BeforeAmountCalculatedColumn
from #Results r;