Difference of two date time in sql server

Question

Is there any way to take the difference between two datetime in sql server?

For example, my dates are

1. 2010-01-22 15:29:55.090

Answer 1

Internally in SQL Server dates are stored as 2 integers. The first integer is the number of dates before or after the base date (1900/01/01). The second integer stores the number of clock ticks after midnight, each tick is 1/300 of a second.

More info here

Because of this, I often find the simplest way to compare dates is to simply substract them. This handles 90% of my use cases. E.g.,

select date1, date2, date2 - date1 as DifferenceInDays
from MyTable
...

When I need an answer in units other than days, I will use DateDiff.