How to find out which Service Pack is installed on SQL Server?

Question

How can I find out which Service Pack is installed on my copy of SQL Server?

Answer 1

From TechNet: Determining which version and edition of SQL Server Database Engine is running

-- SQL Server 2000/2005
SELECT  SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')

-- SQL Server 6.5/7.0
SELECT @@VERSION

Answer 2

Select @@Version

Ex: My machine has the following one installed.

Microsoft SQL Server 2008 R2 (RTM) - 10.50.1600.1 (Intel X86) Apr 2 2010 15:53:02 Copyright (c) Microsoft Corporation Enterprise Edition on Windows NT 6.1 (Build 7601: Service Pack 1)