May be this query will help your problem
CREATE TABLE #Temp (Name varchar(100), value int)
INSERT INTO #Temp
SELECT 'Day1', 12
UNION
SELECT 'Day2' ,6
UNION
SELECT 'Day3' , 10
UNION
SELECT 'Day4' ,8
UNION
SELECT 'Day5' ,4
;with cte as
(
select *, ROW_NUMBER() over(PARTITION by null order by Name ) as Id
FROM #Temp
)
SELECT b.Name , SUM(A.value ), B.Id
FROM cte A
INNER JOIN cte B on A.Id <= B.Id
GROUP BY B.Name , b.id