Joining Timestamps and Time Intervals + SQL Server 2012

Question

I'm trying to compile a report for the uptime of some assets grouped into 10 minute intervals, with the time the asset went down reported on in the next 10 minute block and any block it crosses into.
Currently I have two tables the first is a Calendar table with entries for each 10 minute block which creates my time intervals for the month.
CalendarDate
01/01/2015 20:20:00
01/01/2015 20:30:00
01/01/2015 20:40:00
Etc.
The second table is my Events table which gives me the start of the down time and the end of the down time along with some other useful data.
StartTime:-01/01/2015 20:29:25
EndTime:-01/01/2015 21:42:54
Asset:-Asset01
EventCode:-Event01
TimeOnRoundedUp:-01/01/2015 20:30:00
TimeOffRoundedUp:-01/01/2015 21:20:00
And
StartTime:-01/01/2015 22:01:31
EndTime:-01/01/2015 22:02:01
Asset:-Asset01
EventCode:-Event01
TimeOnRoundedUp:-01/01/2015 22:10:00
TimeOffRoundedUp:-01/01/2015 22:10:00
There is only 1 Event active per Asset at any given time but many events for different assets, some events only last 30 seconds and are within the same 10 minute reporting period, other events span one or more periods.
The result set I'd like to see is grouped by CalanderDate, Asset and EventCode showing the total number of seconds in the ten minute window the asset was running.
Using the two examples above I'd like to see the two rows below:-
CalendarDate, Asset, EventCode, RunningTimeSeconds
01/01/2015 20:30:00, Asset01, Event01, 565 (600-35)
01/01/2015 20:40:00, Asset01, Event01, 0 (600-600)
01/01/2015 20:50:00, Asset01, Event01, 426 (600-174)
01/01/2015 21:00:00, (600-0)
01/01/2015 21:10:00, Asset01, Event01, 570 (600-30)
For the Events that Start and Stop in the same interval I can get those, using DATEDIFF, it's the Events that happen to span one of more periods I can't work out.
I can add additional columns to the tables if needed.
Any and all help is greatly welcomed, thank you for reading my post.
Mark

Answer 1

Give this a go:
DECLARE @calendar TABLE (dateTime DATETIME)
DECLARE @daTetime DATETIME = '2015-01-01'
SET NOCOUNT ON
WHILE CAST(@dateTime AS DATE) = '2015-01-01'
BEGIN
INSERT INTO @calendar (dateTime) VALUES (@dateTime)
SET @dateTime = DATEADD(MINUTE,10,@dateTime)
END
SET NOCOUNT OFF
DECLARE @events TABLE (startDateTime DATETIME, endDateTime DATETIME, asset VARCHAR(20), eventCode VARCHAR(20))
INSERT INTO @events (startDateTime, endDateTime, asset, eventCode)
VALUES ('2015-01-01 02:39:57','2015-01-01 02:59:32','asset01','event01'),('2015-01-01 10:22:57','2015-01-01 13:01:32','asset01','event01'),('2015-01-01 17:38:57','2015-01-01 19:39:32','asset01','event01')
SELECT *,
DATEDIFF(SECOND,
CASE WHEN e.startDateTime >= c.dateTime THEN e.startDateTime
WHEN e.startDateTime < c.dateTime THEN c.dateTime
END,
CASE WHEN e.endDateTime <= DATEADD(MINUTE,10,c.dateTime) THEN e.endDateTime
WHEN e.endDateTime > DATEADD(MINUTE,10,c.dateTime) THEN DATEADD(MINUTE,10,c.dateTime)
END
FROM @calendar c
LEFT OUTER JOIN @events e
ON e.startDateTime BETWEEN c.dateTime AND DATEADD(MINUTE,10,c.dateTime)
OR e.endDateTime BETWEEN c.dateTime AND DATEADD(MINUTE,10,c.dateTime)
OR c.dateTime BETWEEN e.startDateTime AND e.endDateTime