Exponential Moving Avg.

Exponential Moving avg is calculated using the formula.
EMA = (Today's Price)* K + (EMA yesterday) * (1-K)
where K = 2 / (N+1)
The user is going to Input the K.

It is something like
F(N) = Price * K + F(N-1) * (1-K)

How can I reference, the previously calculated value in the Next row
calculation. I need to implement this in SQL Server.

I created a Stored procedure to do this and I used a Temp tbale with
Identity.

Create Table #TempMovAvg
(MID int identity(1,1) Primary key, tempDate DateTime, tValue float)

I Populate the data for that temp table using the below query.

Insert Into #TempMovAvg (tempDate, tValue)
Select Date, Price From DataTable


I tried Diff options to calculate the exponential Moving Avg using the
above formula, but none of them are giving the correct answers. I am
not able to reference the Prev Calculated value in the Next row
calculation.


Some queries I used.
Select a.TempDate, a.tValue,0.9*A.tValue+0.1*
(Select 0.9*t1.tValue+0.1*t2.tValue From #TempMovAvg t1, #TempMovAvg
t2 Where t1.MID=A.MID and t2.MID=t1.MID-1)
FROM #TempMovAvg A
Where A.MID>=2
order by a.TempDate

SELECT A.MId,
SUM(CASE WHEN B.MID=A.MID THEN 0.9*B.tValue
ELSE 0.1*A.tValue END) exponential_average
FROM #TempMovAvg A, #TempMovAvg B
WHERE A.MID>=2 AND A.MID BETWEEN B.MID AND B.MID+1
GROUP BY A.MID

Any help will be greatly appreciated.

thanks
Ganesh