Recommendation first: if you are not sure whether to choose Datetime or Datetime2 the answer is choose Datetime2. Why?
- Higher precision – up to 7 fractional digits for datetime2 vs 3 for datetime
- Higher level of accuracy – datetime rounds the last digit to an increment of .000, .003 or .007 whereas datetime2 supports accuracy of 100 nanoseconds
- Wider range of values – datetime2 supports dated from 0001-01-01 00:00:00 to 9999-12-31 23:59:59.9999999 whereas datetime supports dates from 1753-01-01 00:00:00 to 9999-12-31 23:59:59.997
- Space requirements – depending on the fractional precision you require datetime2 needs from 6 Bytes to 8 bytes of space whereas datetime requires 8 bytes
- Compliance with standards: datetime2 is compliant with both ANSI and ISO 8601 whereas datetime is not.
For a more in depth review of those reasons you can check our other post here.