Это лучшее, что я придумал до сих пор:
declare @start datetime
declare @fin datetime
select @start = dateadd(second, 60, '2008-01-01'), @fin = dateadd(second, 60, '2008-01-04')
select ServerId, State, Total = sum(
case when StartTime > @start and DateAdd(second, Seconds, StartTime) <= @fin
then Seconds
when StartTime < @start and DateAdd(second, Seconds, StartTime) <= @fin
then DateDiff(second, @start, DateAdd(second, Seconds, StartTime))
when StartTime < @start and DateAdd(second, Seconds, StartTime) >= @fin
then DateDiff(second, @start, @fin)
else
DateDiff(second,StartTime,@fin)
end)
into #t
from ServerStatus
where @start < dateadd(second, Seconds, StartTime)
and @fin > StartTime
group by ServerId, State
insert #t
select ServerId, 'unknown', DateDiff(second, @start, @fin) - sum(Total)
from #t
group by ServerId
having DateDiff(second, @start, @fin) > sum(Total)
select * from #t
order by ServerId, State