While I certainly find time calculus fun - I usually find it a LOt more readable to simply get there using date substraction, and pulling out the parts I need, as in something like:
declare @startdate datetime;
declare @enddate datetime;
declare @diff datetime;
set @startdate='2012-05-01 15:12:00.230';
set @enddate='2013-12-11 21:48:00.530';
select @diff=@enddate-@startdate;
select cast(datediff(day,0,@diff) as varchar(20))+':'
+cast(datepart(hour,@diff) as varchar(20))+':'
+cast(datepart(MINUTE,@diff) as varchar(20))+':'
+cast(datepart(SECOND,@diff) as varchar(20))
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Your lack of planning does not constitute an emergency on my part...unless you're my manager...or a director and above...or a really loud-spoken end-user..All right - what was my emergency again?