Hi

Jeff Moden wrote a comprehensive article which covers what you want to do and investigates the various methods used

http://www.sqlservercentral.com/articles/T-SQL/68467/

Here's an example using the triangular join method and the quirky update method

SELECT * INTO #MyTable

FROM (VALUES(1,19), (2,90), (3,20), (4,8), (5, 9)) AS M(ID, VALUE)

-- triangular join

select ID

, VALUE

, (

SELECT SUM(VALUE)

FROM #MyTable b

WHERE b.ID <= a.ID

) AS RUNNING_TOTAL

FROM #MyTable a

-- quirky update

ALTER TABLE #MyTable ADD CONSTRAINT mt_pk PRIMARY KEY (ID)

ALTER TABLE #MyTable ADD RUNNING_TOTAL INT

ALTER TABLE #MyTable ADD RUNNING_CALC VARCHAR(100)

DECLARE @runningTotal int = 0

DECLARE @runningCalc varchar(100) = null

UPDATE #MyTable

SET @runningTotal = RUNNING_TOTAL = @runningTotal + VALUE

,@runningCalc = RUNNING_CALC = isnull(@runningCalc + ' + ','') + CAST(VALUE AS VARCHAR(10))

SELECT * FROM #MyTable

DROP TABLE #MyTable