Comments by World Traveler (Top 1 by date)

DECLARE @Temp TABLE (
SL INT,
GroupName NVARCHAR(100),
Amount DECIMAL(18,2)
)

INSERT INTO @Temp VALUES(1,'Number-1',5)
INSERT INTO @Temp VALUES(2,'Number-2',8)
INSERT INTO @Temp VALUES(3,'Number-3',2)


SELECT T1.SL,
T1.GroupName,
T1.Amount,
SUM(T2.Amount) as CumulativeSum
FROM @Temp T1 INNER JOIN
@Temp T2 on T1.SL >= T2.SL
GROUP BY T1.SL,T1.GroupName, T1.Amount
ORDER BY T1.SL

for more:http://cybarlab.blogspot.com/2013/06/cumulative-sum-in-sql.html