Does DATETIME type include timezone information?

Question

I want to use UTC timestamps exclusively in an MSSQL database. When writing the current timestamp I can use system methods like GETDATEUTC and we have agreed with suppliers that timestamps sent from external sources will also be provided as implicit UTC - but when writing these to the DB do I need to tell MSSQL that it is a UTC date somehow? Or is it my responsibility to know what timezone I'm using?

Answer 1

To provide an answer, in short Neither Datetime nor Datetime2 encodes timezone information, only the raw date/time data specified. It is up to the developers/DBAs/users to agree what the data means.

Answer 2

No, a DATETIME is independent of any time zone.

It is simply an abstract representation of instant in time; that instant represents different times/dates in different time zones, but it is the same instant in time in all of them, and thus the same DATETIME.

You can convert it to a specific time zone using AT TIME ZONE. That will give you a datetimeoffset representing the time and date in a particular time zone that corresponds to that instant in time.