Data:
EmpNumber, TimeStamp, AreaName 10632, 2009-11-23 16:40:33.000, OUT_1 10632, 2009-11-23 16:39:03.000, IN_1 10632, 2009-11-23 16:38:56.000, IN_1 10632, 2009-11-23 15:31:51.000, OUT_1 10632, 2009-11-23 15:31:48.000, IN_1 10632, 2009-11-23 15:31:43.000, IN_1 10632, 2009-11-23 15:31:14.000, OUT_1 10632, 2009-11-23 15:31:08.000, IN_1 10632, 2009-11-23 15:29:18.000, OUT_1 10632, 2009-11-23 15:28:29.000, IN_1 10632, 2009-11-23 15:27:35.000, OUT_1 10632, 2009-11-23 15:26:35.000, IN_1 10632, 2009-11-23 15:22:55.000, IN_1
Here is the query I am currently using.
SELECT [EmpNumber], [TimeStamp], [AreaName],
DATEDIFF(second, [TimeStamp], (SELECT TOP 1 [TimeStamp]
FROM [EventTable] EV2
WHERE EV2.[TimeStamp] > EV1.[TimeStamp]
AND AreaName = 'OUT_1'
AND EV2.[EmpNumber] = EV1.[EmpNumber])
)/60.00 DurationMins
FROM [EventTable] EV1
WHERE AreaName = 'IN_1'
ORDER BY [TimeStamp] DESC
The problem is on the multiple IN_1 entries. I would only like to track the time difference between the first IN_1 Entry, and the Following OUT_1 Entry and Ignore the IN_1 entry in between. Of course you could have 100 IN_1 but the time is only tracked from the first IN_1 to the next OUT_1.
To complicate things further there could be an IN_1, IN_2, IN_3, OUT_1, OUT_2, OUT_3 and you could enter IN_1 and Leave OUT_3 and and it would work just as it was IN_1, OUT_1.