Select 行，直到运行总和达到特定值

Question

我有以下数据：

DECLARE @t TABLE (usr VARCHAR(100), dt DATE, amount INT);
INSERT INTO @t VALUES
('a', '2018-01-01', 100), -- 100
('a', '2018-02-01', 100), -- 200
('a', '2018-03-01', 100), -- 300
('a', '2018-04-01', 100), -- 400
('a', '2018-05-01', 100), -- 500
('b', '2018-01-01', 150), -- 150
('b', '2018-02-01', 150), -- 300
('b', '2018-03-01', 150), -- 450
('b', '2018-04-01', 150), -- 600
('b', '2018-05-01', 150); -- 750

还有一个值，例如 300 或 301（用户变量或列）。我想要 select 行，直到运行总金额达到指定值，具有以下扭曲：

对于 300，我想 select a 的前 3 行和 b 的前 2 行
对于 301，我想 select a 的前 4 行和 b 的前 3 行

这应该很简单，但我找到的解决方案无法处理第二种情况。

Answer 1

DECLARE @t TABLE (usr VARCHAR(100), dt DATE, amount INT);
INSERT INTO @t VALUES
('a', '2018-01-01', 100), -- 100
('a', '2018-02-01', 100), -- 200
('a', '2018-03-01', 100), -- 300
('a', '2018-04-01', 100), -- 400
('a', '2018-05-01', 100), -- 500
('b', '2018-01-01', 150), -- 150
('b', '2018-02-01', 150), -- 300
('b', '2018-03-01', 150), -- 450
('b', '2018-04-01', 150), -- 600
('b', '2018-05-01', 150); -- 750

DECLARE @Total INT = 301;

WITH cte AS
(
    SELECT *, SUM(amount) OVER (PARTITION BY usr ORDER BY dt) AS RunTotal
    FROM @t
)
SELECT *
FROM   cte
WHERE  cte.RunTotal - cte.amount < @Total -- running total for previous row is less
                                          -- than @Total then include current row

Answer 2

DECLARE @t TABLE (usr VARCHAR(100), dt DATE, amount INT);
INSERT INTO @t VALUES
('a', '2018-01-01', 100), -- 100
('a', '2018-02-01', 100), -- 200
('a', '2018-03-01', 100), -- 300
('a', '2018-04-01', 100), -- 400
('a', '2018-05-01', 100), -- 500
('b', '2018-01-01', 150), -- 150
('b', '2018-02-01', 150), -- 300
('b', '2018-03-01', 150), -- 450
('b', '2018-04-01', 150), -- 600
('b', '2018-05-01', 150); -- 750

declare @target int = 300;

with cte_RunningTotal as
(
    select  
        usr,
        dt,
        amount,
        sum(amount) over (partition by usr order by dt rows unbounded preceding) as runningTotal
    from @t 
)
select *
from cte_RunningTotal 
where runningTotal < @target + amount
order by usr, dt

Select 行，直到运行总和达到特定值

Select rows until running sum reaches specific value

sql

sql-server

window-functions

sql-server-2012

Select 行，直到 运行 总和达到特定值

Select rows until running sum reaches specific value

sql

sql-server

window-functions

sql-server-2012

Select 行，直到运行总和达到特定值