Here is part of database:
SessionID SessionStartTime SessionCloseTime
24 2012-10-16 01:00:06.000 2012-10-16 01:01:22.000
24 2012-10-16 01:00:08.000 2012-10-16 01:01:10.000
24 2012-10-16 01:00:16.000 2012-10-16 01:01:12.000
24 2012-10-16 01:00:30.000 2012-10-16 01:01:48.000
24 2012-10-16 01:00:41.000 2012-10-16 01:02:08.000
24 2012-10-16 01:00:48.000 2012-10-16 01:01:34.000
24 2012-10-16 01:00:56.000 2012-10-16 01:03:09.000
24 2012-10-16 01:01:02.000 2012-10-16 01:02:13.000
24 2012-10-16 01:01:05.000 2012-10-16 01:03:16.000
24 2012-10-16 01:01:09.000 2012-10-16 01:02:42.000
24 2012-10-16 01:01:15.000 2012-10-16 01:02:48.000
24 2012-10-16 01:01:18.000 2012-10-16 01:02:14.000
24 2012-10-16 01:01:18.000 2012-10-16 01:02:06.000
24 2012-10-16 01:01:42.000 2012-10-16 01:03:16.000
24 2012-10-16 01:01:45.000 2012-10-16 01:03:04.000
I want to add a new column to this table named as SessionCount and then I will be able to see the call peaks I mean max count of sessions which happened at the same time.
This table should be like this:
SessionID SessionStartTime SessionCloseTime SessionCount
24 2012-10-16 01:00:06.000 2012-10-16 01:01:22.000 1
24 2012-10-16 01:00:08.000 2012-10-16 01:01:10.000 2
24 2012-10-16 01:00:16.000 2012-10-16 01:01:12.000 3
24 2012-10-16 01:00:30.000 2012-10-16 01:01:48.000 4
24 2012-10-16 01:00:41.000 2012-10-16 01:02:08.000 5
24 2012-10-16 01:00:48.000 2012-10-16 01:01:34.000 6
24 2012-10-16 01:00:56.000 2012-10-16 01:03:09.000 7
24 2012-10-16 01:01:02.000 2012-10-16 01:02:13.000 8
24 2012-10-16 01:01:05.000 2012-10-16 01:03:16.000 9
24 2012-10-16 01:01:09.000 2012-10-16 01:02:42.000 10
24 2012-10-16 01:01:15.000 2012-10-16 01:02:48.000 10
24 2012-10-16 01:01:18.000 2012-10-16 01:02:14.000 11
24 2012-10-16 01:01:18.000 2012-10-16 01:02:06.000 11
24 2012-10-16 01:01:42.000 2012-10-16 01:03:16.000 7
24 2012-10-16 01:01:45.000 2012-10-16 01:03:04.000 7
so in this table there are maximum 11 call peaks happened at the same time at 01:01:18. There are 11 active calls at 01:01:18. How can I calculate the sessions when session is active then +1 when session is finished then -1?