SQL Server Developer Edition 2012 or 2014 - Download
Developer Edition is free
As of March 31, 2016 Microsoft SQL Server Developer Edition is now free for SQL Server 2014 and up for Visual Studio Dev essential members (which is free as well).
For all editions, see How to buy SQL Server.
If you want to explore SQL Server, you can download SQL Server Evaluation Edition for 180 days, and then purchase it.
- Microsoft® SQL Server® 2014 & 2016 Evaluation
- Microsoft® SQL Server® 2012 Evaluation
It is now free as of 31 March 2016:
Microsoft SQL Server Developer Edition is now free (SQL Server Team Blog)
You can upgrade your current SQL Express edition to Developer:
- Download the appropriate edition (x86 or x64)
- Mount the .iso and run the installer package
- Select "Maintenance"
- Select "Edition Upgrade"
- Follow the prompts and select the Express instance that you wish to upgrade.
To enable SQL Agent:
sp_configure 'show advanced options', 1
RECONFIGURE
GO
sp_configure 'agent xps', 1
RECONFIGURE
GO
sp_configure