Installing MSSQL Express Versions

You would expect installing the Express version of MS SQL Server to be a straightforward task, but in that you'd be wrong.  Firstly, these are the different released versions of SQL Server Express (as of Oct 2011):

• MSSQL 2005
• MSSQL 2005 SP1
• MSSQL 2005 SP2
• MSSQL 2005 SP3
• MSSQL 2005 SP4

• MSSQL 2008
• MSSQL 2008 SP1
• MSSQL 2008 SP2
• MSSQL 2008 R2
• MSSQL 2008 R2 SP1
• MSSQL 2008 R2 SP2

These are all still available for download, with no warnings on the download page that versions are obsolete.

On top of this, there are three or four different bundles you can download, depending on the features you want - in both 32 (x86) and 64 bit (x64) versions.
The names of features change regularly between versions of MSSQL and sometime even between service packs.

What are your chances of getting the correct latest download ? Not good !

This post will provide links to the combinations you want and guide you through the installation process.

The Ins and Outs of MSSQL Updates

MSSQL service packs have the following behaviour

• updating from an older to newer service pack level essentially reinstalls MSSQL from scratch, so you really don't want to install an old version and update it. However, the advantage of this way of doing things is that you don't have to apply the service packs in order - you can skip straight to the latest
• as soon as you attach your database (mdf) files to the new server, they will be updated to the new server's version format and from that point on the files will not work with an earlier service pack or version of SQL
• for this reason you MUST get the correct server release (2000, 2005, 2008) AND SP level (0-4).  In addition, ALWAYS make a copy of important databases (backups or copies of properly detached mdf files) before installing a Service Pack.

MSSQL Features

There are essentially three features of MSSQL.

• the core server
• client/developer tools (MSSQL Management Studio or MSSMS and a command line query tool) -  these are used during development and/or troubleshooting
• Business Intelligentce (BI)/Anaysis Services and Reporting Services

There will be downloads for (a) core only (b) core + developer tools, (c) core + dev tools + BI/reporting

Checklist

So in summary, you need to decide these points before proceeding:

1. which version of SQL Server Express do you want (2005 or 2008) ?
2. are you installing on a 64 bit or 32 bit Operating System ? (note: this is not necessarily the same as the hardware, as you can run a 32 bit OS on a 64 bit processor)
3. what features do you require from the above list ?

The proceed to the post specific to your version