DECLARE @START_DATE DATETIME
DECLARE @END_DATE DATETIME
SET @START_DATE ='2014-07-02 07:59'
SET @END_DATE = '2014-07-02 18:03'
SELECT CONVERT(VARCHAR(12), DATEADD(MS, DATEDIFF(MS, @START_DATE, @END_DATE), 0), 114) AS TimeDiff
--code credited by: syed shanu