Executive Summary: Each build of SQL Server has a version number. To find your version of SQL Server, open SQL Server Management Studio (SSMS). The version number is listed immediately following the system name in the Object Browser. SQL Server 2008, 2005, and 2000 versions are listed in a table attached to this article.

Most organizations considering SQL Server 2008 have installed one or more community technology preview (CTP) or release candidates, and my office, too, has multiple SQL Server installations. Recently, I was surprised to find that one of the systems that I thought was running the SQL Server 2008 Release to Manufacturing (RTM) code was actually still running one of the release candidates.

Each build of SQL Server that Microsoft releases has its own version number. For example, the SQL Server 2008 RTM gold code is version number 100.00.1600.22. Any lower version number indicates that you’re running prerelease code.

To find your version of SQL Server, open SQL Server Management Studio (SSMS). The version number is listed immediately following the system name in the Object Browser. You can also find the version number by running the following T-SQL statement

SELECT @@version

Table 1 shows all the recent version numbers for SQL Server 2008. It also lists version numbers for previous production releases back to SQL Server 2000.

If you find, like I did, that one of your systems is release-candidate level or earlier, and you want to move it to the RTM code, don’t attempt to perform an upgrade. It’s not a supported scenario and could cause you to wind up with mixed binaries on the system, potentially leading to problems.

Instead, to get from the release-candidate level to the RTM code, you need to completely uninstall the prerelease code. Then you can go ahead and install the production SQL Server code and reattach your databases. However, if you’re running an older production version of SQL Server 2005 or SQL Server 2000, you can perform an in-place upgrade to move directly to SQL Server 2008.