Sum HH:MM:SS in Sql Server

Question

I have searched and came out with no concrete answer on the best way to sum up hours, minute and seconds in using T_Sql.
I have a query like below
SELECT TaxPayer
, STR(SUM(Elapsed)/3600)
+ RIGHT(CONVERT(char(8),DATEADD(s,SUM(Elapsed),0),108),6)AS Elapsed
-- , ISNULL(SUM(Elapsed),0) AS Elapsed
FROM (
SELECT TaxPayerID AS CallRef
, TaxPayer
, CONVERT(VARCHAR(10),DateTimeOn,101) AS StartDate
, CONVERT(VARCHAR(8),DateTimeOn,108) AS StartTime
, CONVERT(VARCHAR(10),DateTimeOff,101) AS FinishedDate
, CONVERT(VARCHAR(8),DateTimeOff,108) AS FinishedTime
, CONVERT(VARCHAR(6), DATEDIFF(second, A.DateTimeOn, A.DateTimeOff)/3600)
+ ':'
+ RIGHT('0' + CONVERT(VARCHAR(2), (DATEDIFF(second, A.DateTimeOn, A.DateTimeOff) % 3600) / 60), 2)
+ ':'
+ RIGHT('0' + CONVERT(VARCHAR(2), DATEDIFF(second, A.DateTimeOn, A.DateTimeOff) % 60), 2) AS Elapsed
FROM dbo.TestTable A WITH(NOLOCK)
WHERE ProblemID > 0
)AS B
GROUP BY TaxPayerID
, TaxPayer
How do I sum up Elapsed in H:M:S format?
Thank you
Zionlite

Answer 1

(Sum(Fields!TIME.Value.TotalSeconds) / 3600) & ":"
& ((Sum(Fields!TIME.Value.TotalSeconds) Mod 3600) / 60) & ":"
& ((Sum(Fields!TIME.Value.TotalSeconds) Mod 3600) Mod 60)
Mark as answer if it is useful