How to calculate running total grouped by Order No - sql-server-2008

Question

Trying to create a running total for orders in SQL Server 2008, similar to the below table (Order No & Order Total columns exist in my SQL Server table), tried using a recursive cte but my results were a running total for all orders, not grouped by order no. Any suggestions how to have the running total grouped by the order no? Thanks
---------------------------------------------------------
| Order No. | Order Total | Running Total for Order No |
---------------------------------------------------------
| 1 | $10,000 | $10,000 |
---------------------------------------------------------
| 1 | -$5,000 | $5,000 |
---------------------------------------------------------
| 1 | $3,000 | $8,000 |
---------------------------------------------------------
| 2 | $2,500 | $2,500 |
---------------------------------------------------------
| 2 | $5,000 | $7,500 |
---------------------------------------------------------
| 2 | $4,000 | $11,000 |
---------------------------------------------------------

Answer 1

I would do this is with an Instead of Insert Trigger. The trigger would subtract/add from the groups first value. Obviously this should of been done at the creation of the table but you could add it after you make table update.
Keep in mind in order for the below code to work, you would need a primary key on the Order table
CREATE TABLE Orders
(
id INT IDENTITY(0, 1) PRIMARY KEY
, orderNo INT
, orderTotal MONEY
, runningTotal MONEY
);
INSERT INTO Orders
VALUES
(1,10000,10000),
(1,-5000,5000),
(1,3000,8000),
(2,2500,2500),
(2,5000,7500),
(2,4000,11500);
GO
--CREATE TRIGGER
CREATE TRIGGER trg_RunningTotal ON Orders
INSTEAD OF INSERT
AS
BEGIN
DECLARE #PreviousTotal MONEY =
(
SELECT TOP 1
a.runningTotal
FROM Orders AS a
INNER JOIN INSERTED AS b ON a.orderNo = b.orderNo
WHERE a.orderno = b.Orderno
ORDER BY a.id DESC
);
INSERT INTO Orders
SELECT
orderno,
orderTotal,
(#PreviousTotal + orderTotal) AS runningTotal
FROM INSERTED;
END;
--Insert new record
INSERT INTO orders
VALUES
(1,1000,NULL);
--View newly added record
SELECT
*
FROM orders
WHERE orderno = 1;

Answer 2

You need to following query:
SELECT orderno,
SUM((CASE WHEN ISNUMERIC(ordertotal)=1
THEN CONVERT(MONEY,ordertotal) ELSE 0 END)
)
AS [Converted to Numeric]
FROM price group by orderno