SQL Server: datediff function resulted in an overflow when using MILLISECOND

A bit later response but may help. In SQL 2016 MS introduced function DATEDIFF_BIG which will (according to type size) overflow in difference bigger than something like 290k years. But technet article have same time difference as basic DATEDIFF - https://msdn.microsoft.com/en-us/library/mt628058.aspx

In SQL Server 2016 there is a new function available: DATEDIFF_BIG

It solves exactly the overflow problem.

See https://docs.microsoft.com/en-us/sql/t-sql/functions/datediff-transact-sql?view=sql-server-ver15#return-value

For millisecond, the maximum difference between startdate and enddate is 24 days, 20 hours, 31 minutes and 23.647 seconds.

If you need millisecond above that level, you'll need to write something custom.