SQL Server 2016 introduced a new function for data operation which is DATEDIFF_BIG().
Previously, we were unable to take date difference in format of MICROSECOND, NANOSECOND, MILLISECOND using DATADIFF().
In our new module, we need to make time difference in a microsecond as we are dealing with financial transactions.

If you are using DATEDIFF() and try to get date difference in format of MICROSECOND, NANOSECOND, MILLISECOND, you will get a below error.
Because the return value from the DATEDIFF function is an integer with a range of -2^31 to 2^31 – 1.

SELECT DATEDIFF(MICROSECOND,'2015-08-26 09:12:56.147488','2016-10-30 08:09:14.965238')
SELECT DATEDIFF(NANOSECOND,'2015-08-26 09:12:56.147488','2016-10-30 08:09:14.965238')
SELECT DATEDIFF(MILLISECOND,'2015-08-26 09:12:56.147488','2016-10-30 08:09:14.965238')

Msg 535, Level 16, State 0, Line 1
The datediff function resulted in an overflow. The number of dateparts separating two date/time instances is too large. Try to use datediff with a less precise datepart.

In SQL Server 2016, we can use DATEDIFF_BIG() to take date difference in format of MICROSECOND, NANOSECOND, MILLISECOND.

SELECT DATEDIFF_BIG(MICROSECOND,'2015-08-26 09:12:56.147488','2016-10-30 08:09:14.965238')
SELECT DATEDIFF_BIG(NANOSECOND,'2015-08-26 09:12:56.147488','2016-10-30 08:09:14.965238')
SELECT DATEDIFF_BIG(MILLISECOND,'2015-08-26 09:12:56.147488','2016-10-30 08:09:14.965238')