Understanding SQL version numbers can be a bit confusing at times and remembering the builds an even bigger hassle. I just replied with the following post on MSDN recently. I thought I would convert the post into a blog post for other people to see and use as appropriate.
SQL Server has the following components:
1. Database engine (Engine, Replication, Full-text)
2. SSIS – Integration Services (SQL Server 2005 and above)
3. Reporting Services
4. Tools and Shared Components (Eg. SSMS)
5. Notification Services (SQL Server 2005 and above)
6. Analysis Services
When you install a SQL Server component, the RTM version of that component is installed. The SQL Server release version has a version major number which will stay constant for a release. The 4 digit number that keeps varying is the build number of the current version of your component. This number changes whenever you apply a hotfix/security fix/cumulative update/service pack for that particular component of SQL Server. Very rarely do the build numbers remain constant across patches (Seen to happen in Reporting Services for certain builds).
Version major numbers: This is the first number in the version output:
SQL Server 7.0 – 7.00.XXXX
SQL Server 2000 – 8.00.XXXX
SQL Server 2005 – 9.00.XXXX
SQL Server 2008 – 10.00.XXXX
SQL Server 2008 R2- 10.50.XXXX
The above article has all the build numbers that were released for SQL Server.