What are the possible ways to determine the deployed SQL Server version?

Method 1: Connect to the instance of SQL Server, and then run the following query:

Select @@version

An example of the output of this query is as follows:

Microsoft SQL Server 2008 (SP1) - 10.0.2531.0 (X64)   Mar 29 2009 
10:11:52   Copyright (c) 1988-2008 Microsoft Corporation  Express 
Edition (64-bit) on Windows NT 6.1 <X64> (Build 7600: )