Running Total SQL-Server

DATA
OrderID OrderAmt OrderDate
----------- ---------- --------------------
1 10.50 2003-10-11 08:00:00
2 11.50 2003-10-11 10:00:00
3 1.25 2003-10-11 12:00:00
4 100.57 2003-10-12 09:00:00
5 19.99 2003-10-12 11:00:00
6 47.14 2003-10-13 10:00:00
7 10.08 2003-10-13 12:00:00
8 7.50 2003-10-13 19:00:00
9 9.50 2003-10-13 21:00:00
---------------------------
select O.OrderId,
convert(char(10),O.OrderDate,101) as 'Order Date',
O.OrderAmt,
(select sum(OrderAmt) from Orders
where OrderID <= O.OrderID and
convert(char(10),OrderDate,101)
= convert(char(10),O.OrderDate,101))
'Running Total'
from Orders O
order by OrderID
--------------------------------------
select O.OrderID,convert(char(10),O.OrderDate,101) 'Order Date',O.OrderAmt,
case when OrderID = (select top 1 OrderId from Orders
where convert(char(10),OrderDate,101)
= convert(char(10),O.OrderDate,101)
order by OrderID desc)
then (select cast(sum(OrderAmt) as char(10))
from Orders
where OrderID <= O.OrderID
and convert(char(10),OrderDate,101)
= convert(char(10),O.OrderDate,101))
else ' ' end as 'Sub Total',
case when OrderID = (select top 1 OrderId from Orders
order by OrderDate desc)
then (select cast(sum(OrderAmt) as char(10))
from Orders)
else ' ' end as 'Grand Total'
from Orders O
order by OrderID