Calculating total time excluding overlapped time & breaks in SQLServer

Question

From the list of start time and end times from a select query, I need to find out the total time excluding overlapping time and breaks.

StartTime                         


        

Answer 1

DECLARE @table TABLE (StartTime DateTime2, EndTime DateTime2)

INSERT INTO @table SELECT '2014-10-01 10:30:00.000', '2014-10-01 12:00:00.000'
INSERT INTO @table SELECT '2014-10-01 10:40:00.000', '2014-10-01 12:00:00.000'
INSERT INTO @table SELECT '2014-10-01 10:42:00.000', '2014-10-01 12:20:00.000'
INSERT INTO @table SELECT '2014-10-01 10:40:00.000', '2014-10-01 13:00:00.000'
INSERT INTO @table SELECT '2014-10-01 10:44:00.000', '2014-10-01 12:21:00.000'
INSERT INTO @table SELECT '2014-10-13 15:50:00.000', '2014-10-13 16:00:00.000'


;WITH addNR AS ( -- Add row numbers

    SELECT StartTime, EndTime, ROW_NUMBER() OVER (ORDER BY StartTime, EndTime) AS RowID
    FROM @table AS T

), createNewTable AS ( -- Recreate table according overlap time

    SELECT StartTime, EndTime, RowID 
    FROM addNR
    WHERE RowID = 1

    UNION ALL

    SELECT 
        CASE 
            WHEN a.StartTime <= AN.StartTime AND AN.StartTime <= a.EndTime THEN a.StartTime 
            ELSE AN.StartTime END AS StartTime, 
        CASE WHEN a.StartTime <= AN.EndTime AND AN.EndTime <= a.EndTime THEN a.EndTime 
            ELSE AN.EndTime END AS EndTime,
        AN.RowID 
    FROM addNR AS AN
    INNER JOIN createNewTable AS a
        ON a.RowID + 1 = AN.RowID

), getMinutes AS ( -- Get difference in minutes
    SELECT DATEDIFF(MINUTE,StartTime,MAX(EndTime)) AS diffMinutes
    FROM createNewTable
    GROUP BY StartTime
)
SELECT SUM(diffMinutes) AS Result
FROM getMinutes

And the result is 160