CREATE TABLE #DateTable (Time_Stamp datetime, Working_Hour int)
INSERT INTO #DateTable (Time_Stamp, Working_Hour)
VALUES
 ('2016-12-05 14:00:00',1)
,('2016-12-05 15:00:00',1)
,('2016-12-05 16:00:00',1)
,('2016-12-05 17:00:00',0)
,('2016-12-05 18:00:00',0)
,('2016-12-05 19:00:00',0)
,('2016-12-05 20:00:00',0)
,('2016-12-05 21:00:00',0)
,('2016-12-05 22:00:00',0)
,('2016-12-05 23:00:00',0)
,('2016-12-05 00:00:00',0)
,('2016-12-05 01:00:00',0)
,('2016-12-05 02:00:00',0)
,('2016-12-05 03:00:00',0)
,('2016-12-05 04:00:00',0)
,('2016-12-05 05:00:00',0)
,('2016-12-05 06:00:00',0)
,('2016-12-05 07:00:00',0)
,('2016-12-05 08:00:00',0)
,('2016-12-05 09:00:00',0)
,('2016-12-05 10:00:00',0)
,('2016-12-05 11:00:00',0)
,('2016-12-05 12:00:00',1)
,('2016-12-05 13:00:00',1)
,('2016-12-05 14:00:00',1)
,('2016-12-05 15:00:00',1)

DECLARE @StartDate datetime = '2016-12-05 15:00:00'
DECLARE @EndDate datetime = '2016-12-06 13:00:00'

SELECT
    SUM(Working_Hour) Working_Hour
FROM #DateTable
WHERE Time_Stamp BETWEEN @StartDate AND @EndDate

Working_Hour
3