Need a sql query to get the difference between two timestamp in the format of hh:mm:ss.msec

Question

I have a database table where it keeps record of the transaction when it starts at StartTime and when it ends at EndTime. Both these entries are having the timestamp entries. Say for example, I have a tuple with Entries like 'Transaction A' starts at '2014-05-07
20:55:03.170' and ends at '2014-05-08 08:56:03.170'. I need to find the difference between these two timestamps and my expected output is 12:01:00.000. Let me know how to achieve this ? 

Answer 1

Hi,
You can use below script which calculates difference as DD:HH:MM:SS. You can modify the same:
DECLARE @startTime DATETIME
DECLARE @endTime DATETIME
SET @startTime = '2013-11-05 12:20:35'
SET @endTime = '2013-11-10 01:22:30'
SELECT [DD:HH:MM:SS] =
CAST((DATEDIFF(HOUR, @startTime, @endTime) / 24) AS VARCHAR)
+ ':' +
CAST((DATEDIFF(HOUR, @startTime, @endTime) % 24) AS VARCHAR)
+ ':' +
CASE WHEN DATEPART(SECOND, @endTime) >= DATEPART(SECOND, @startTime)
THEN CAST((DATEDIFF(MINUTE, @startTime, @endTime) % 60) AS VARCHAR)
ELSE
CAST((DATEDIFF(MINUTE, DATEADD(MINUTE, -1, @endTime), @endTime) % 60)
AS VARCHAR)
END
+ ':' + CAST((DATEDIFF(SECOND, @startTime, @endTime) % 60) AS VARCHAR),
[StringFormat] =
CAST((DATEDIFF(HOUR , @startTime, @endTime) / 24) AS VARCHAR) +
' Days ' +
CAST((DATEDIFF(HOUR , @startTime, @endTime) % 24) AS VARCHAR) +
' Hours ' +
CASE WHEN DATEPART(SECOND, @endTime) >= DATEPART(SECOND, @startTime)
THEN CAST((DATEDIFF(MINUTE, @startTime, @endTime) % 60) AS VARCHAR)
ELSE
CAST((DATEDIFF(MINUTE, DATEADD(MINUTE, -1, @endTime), @endTime) % 60)
AS VARCHAR)
END +
' Minutes ' +
CAST((DATEDIFF(SECOND, @startTime, @endTime) % 60) AS VARCHAR) +
' Seconds '
Reference:
http://sqlandme.com/2013/12/23/sql-server-calculating-elapsed-time-from-datetime/
- Vishal
SqlAndMe.com