Can I install SQL Server alongside SQL Server Express?

Question

I already use a third party application that uses SQL Server Express 2008 as a backend, and thus, installs it onto my PC (Windows 7 Ultimate).

I need to do development work against SQL Server 2012 Web Edition, and so, need to install it onto my PC. Will this cause any conflicts with the app that depends on SQL Server Express? Do I have to migrate data from the SQL Server Express install to SQL Server 2012? (I'm worried that might break stuff since I have no control over the application that uses it.)

Answer 1

Several SQL Server instances can absolutely co-exist on a single system.

Typically, the first instance will be called the default instance and will be addressed as "" (no instance name) - e.g. you connect to it using the local machine name (or IP address), or . or (local) (if connecting to a locally installed default instance).

Any other SQL Server instance on the same machine must be a named instance, e.g. have a unique name. Typically, SQL Server Express is installed as the SQLEXPRESS instance - but that's a convention, not a technical requirement.

As long as you make sure your various instances all have unique names (on that machine they're installed on), you should have no problems running 2 (or even more) instances of SQL Server - with different versions and editions.

Answer 2

This should be fine.

When installing SQL Server on a machine that already has a version installed, you should be prompted for an instance name - this is the instance name you need to connect to.

See this InformIt article for more detail.