How to find out MS SQL Server version

Run this query:

SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')

and you will get a result similar to this

Product Version Product Level Edition
9.00.3042.00 SP2 Express Edition


Another useful query:

SELECT @@VERSION
GO

Will show you this:

Microsoft SQL Server 2005 - 9.00.3042.00 (Intel X86) Feb 9 2007 22:47:07 Copyright (c) 1988-2005 Microsoft Corporation Express Edition on Windows NT 6.0 (Build 6001: Service Pack 1)