Compute datetime field addition

[sunny297]

I used the below block to get the AverageTime field by adding the 2 date columns by first converting them to seconds and then dividing it with a number field.

begin

declare @date1 nvarchar(100), @date2 nvarchar(100), @FinalDate nvarchar(100), @count int

create table #temp6 (tks int, date1 nvarchar(100), date2 nvarchar(100), FinalDate nvarchar(100))

select @count = count(eventcode) from trackedplusimport_temp where deviceid=13768
SELECT @date1 = Convert(nvarchar(10),sum(DatePart(hh,ScanDateTime)))+':'+ Convert(nvarchar(10),sum(DatePart(mi,ScanDateTime)))+':'+ Convert(nvarchar(10),sum(DatePart(ss,ScanDateTime))) FROM trackedplusimport_temp WHERE deviceid=13768
SELECT @date2 = Convert(nvarchar(10),sum(DatePart(hh,DataDateTime)))+':'+ Convert(nvarchar(10),sum(DatePart(mi,DataDateTime)))+':'+ Convert(nvarchar(10),sum(DatePart(ss,DataDateTime))) FROM trackedplusimport_temp WHERE deviceid=13768

SELECT @FinalDate =
convert(nvarchar(10),
(
 (
	(DATEPART(hour, convert(nvarchar,@date1,108)) * 60 * 60) +
	(DATEPART(minute,convert(nvarchar,@date1,108)) * 60) +
	 DATEPART(second, convert(nvarchar,@date1,108))
 )
 +
 (
	(DATEPART(hour, convert(nvarchar,@date2,108)) * 60 * 60) +
	(DATEPART(minute, convert(nvarchar,@date2,108)) * 60) +
	 DATEPART(second, convert(nvarchar,@date2,108))
 )
)
)
--select @c = @b/@count

insert into #temp6 values(@count, @date1, @date2, @FinalDate)

end

--drop table #temp6
--select * from #temp6

When Executing the above, Im getting the below error..


Arithmetic overflow error converting expression to data type datetime


How can I overcome this error?

Thanks in advance

[sunny297]

Just some more info..

When Date1 and Date2 are upto : '23:59:59', the query is working fine. But when it becomes '24:00:00' - I am getting Overflow error.