Late Monday night (October 18, 2010), Microsoft released the latest Cumulative Updates for SQL Server 2005 and for SQL Server 2008 R2. You can get SQL Server 2005 SP3 Cumulative Update 12 and SQL Server 2008 R2 RTM Cumulative Update 4 by following the embedded links. SQL Server 2005 and SQL Server 2008 R2 seem to be on a synchronized CU release cycle, while SQL Server 2008 is not synchronized with the other two major releases.

Here is a “build chart” of the recent Build numbers for SQL Server 2005, 2008, and 2008 R2. If you run SELECT @@VERSION, you will get your Build number, which you can use to determine where you are as far as Service Packs and Cumulative Updates are concerned. If you have a Build number that does not show up in my chart, that probably means you are on a hotfix build, most likely from Microsoft Update.

As you can see, for SQL Server 2005, you need to be on SP3, while for SQL Server 2008, you could be on SP1 or SP2. SQL Server 2008 SP2 has the same fixes that were included in SQL Server 2008 SP1 CU8. If you are on SP1 CU9 or CU10, you should wait for SP2 CU1 to come out before you apply SQL Server 2008 SP2.

-- SQL and OS Version information for current instance
SELECT @@VERSION AS [SQL Server and OS Version Info];
--   SQL 2005 SP2 is now an "unsupported service pack"
--   SQL 2005 SP2 Builds             SQL 2005 SP3 Builds
-- Build       Description        Build       Description
-- 3042        SP2 RTM              4035        SP3 RTM
-- 3161        SP2 CU1              4207        SP3 CU1
-- 3175        SP2 CU2              4211        SP3 CU2 
-- 3186        SP2 CU3              4220        SP3 CU3         
-- 3200        SP2 CU4              4226        SP3 CU4         
-- 3215        SP2 CU5              4230        SP3 CU5          
-- 3228        SP2 CU6              4266        SP3 CU6        
-- 3239        SP2 CU7              4273        SP3 CU7        
-- 3257        SP2 CU8              4285        SP3 CU8
-- 3282        SP2 CU9              4294        SP3 CU9
-- 3294        SP2 CU10             4305        SP3 CU10
-- 3301        SP2 CU11             4309        SP3 CU11
-- 3315        SP2 CU12             4311        SP3 CU12
-- 3325        SP2 CU13
-- 3328        SP2 CU14
-- 3330        SP2 CU15
-- 3355        SP2 CU16
-- 3356        SP2 CU17
-- SP2 Branch is "retired"
-- SQL Server 2008 RTM is considered an "unsupported service pack" as of April 13, 2010
-- SQL Server 2008 RTM Builds     SQL Server 2008 SP1 Builds     SQL Server 2008 SP2 Builds
-- Build       Description        Build        Description         Build     Description
-- 1600        Gold RTM
-- 1763        RTM CU1
-- 1779        RTM CU2
-- 1787        RTM CU3    -->      2531        SP1 RTM
-- 1798        RTM CU4    -->      2710        SP1 CU1
-- 1806        RTM CU5    -->      2714        SP1 CU2 
-- 1812        RTM CU6    -->      2723        SP1 CU3
-- 1818        RTM CU7    -->      2734        SP1 CU4
-- 1823        RTM CU8    -->      2746        SP1 CU5
-- 1828        RTM CU9    -->      2757        SP1 CU6
-- 1835        RTM CU10   -->      2766        SP1 CU7
-- RTM Branch Retired     -->      2775        SP1 CU8      -->    4000       SP2 RTM
--                                 2789        SP1 CU9
--                                 2799        SP1 CU10                                   
-- SQL Server 2008 R2 Builds
-- Build            Description
-- 10.50.1092        August 2009 CTP2
-- 10.50.1352        November 2009 CTP3
-- 10.50.1450        Release Candidate
-- 10.50.1600        RTM
-- 10.50.1702        RTM CU1
-- 10.50.1720        RTM CU2
-- 10.50.1734        RTM CU3
-- 10.50.1746        RTM CU4