How to get running sum of a column in sql server

Question

Hi I have a column with name Qty from table Bills i want a column that show the running sum of Qty column like this :

Qty   Run_Sum
1      1
2      3
3      6
4      10
5      15

Suggest me some appropriate method to make running some thankx

Answer 1

if you RDBMS supports window function,

for SQL Server 2012

SELECT  Qty,
        SUM(Qty) OVER (ORDER BY Qty) AS CumulativeTOTAL
FROM    tableName

• SQLFiddle Demo

for SQL Server 2008

SELECT a.Qty, (SELECT SUM(b.Qty)
               FROM   TableName b
               WHERE  b.Qty <= a.Qty)
FROM   TableName a
ORDER  BY a.Qty;

• SQLFiddle Demo

Answer 2

SQLFiddle demo

SELECT Qty,
SUM(Qty) OVER (ORDER BY Qty) Run_Sum
FROM t ORDER BY Qty

For SQLServer prior to 2012:

select Qty,
(select sum(Qty) from t where Qty<=t1.Qty)
from t t1 order by Qty

SQLFiddle demo

Or also you can do it without subquery:

select t1.Qty, sum(t2.Qty)
from t t1 
join t t2 on (t1.Qty>=t2.Qty)
group by t1.Qty
order by t1.Qty

SQLFiddle demo