In Nutshell, SQL server 2012 comes with Enterprise, Business Intelligence, Standard, Web, Developer, and Express editions. There are number of article available on this so I am not going to write much here. I would encourage you to read about each edition and its features in details. In DBA role, you are expected to provide recommendation for editions. So, you must know which edition will suite the requirements and will be in budget too. Below, is a quick note about available editions

SQL Server 2012 Standard Edition

• It provides the core relational database engine and basic business intelligence (BI) capabilities.
• Limited to 16 Cores
• 64GB of RAM
• It doesn’t include support for the advanced availability features or the more powerful BI features such as PowerPivot, Power View, and Master Data Services.
• It includes support for two-node AlwaysOn Failover Clusters, and it’s licensed either per core or per server. We will talk about Licensing in next chapter. So don’t worry.

SQL Server 2012 Business Edition

• SQL Server 2012 Business Intelligence Edition is a new member of the SQL Server family.
• Limited to 16 cores for the database engine and limited to 64GB of RAM. However, it can use the maximum number of cores supported by the OS for Analysis Services and Reporting Services because this is BI Edition.
• This Edition includes all of the features in the Standard edition and support for advanced BI features such as Power View and PowerPivot, but it lacks support for the advanced availability features like AlwaysOn Availability Groups and other online operations. The BI Edition supports two-node AlwaysOn Failover Clusters, and it’s licensed per server.

SQL Server 2012 Enterprise Edition

• SQL Server 2012 Enterprise Edition has everything that SQL Server offers.
• It supports the maximum number of cores and RAM in the host OS and provides the complete SQL Server feature set, including support for all of the advanced availability and BI features.
• The Enterprise edition supports up to 16-node AlwaysOn Failover Clusters
• AlwaysOn Availability Groups
• PowerPivot, Power View, Master Data Services, advanced auditing, transparent data encryption, the ColumnStore index, and more.
• The Enterprise edition is licensed per core.

SQL Server 2012 Express Editions and LocalDB

SQL Server 2012 offers free edition as SQL Server Express Edition.

• The Express editions are limited to support for one CPU and 1GB of RAM. Databases are limited to 10GB per database.
• A new option called LocalDB is also available.

SQL Server 2012 express edition comes in three versions

1. Express (Database Only)
2. Express with Tools
3. Express with Advanced Services. Microsoft will also continue to offer a download of SQL Server Management Studio Express.

SQL Server 2012 Web and Developer Editions

SQL Server 2012 Web Edition and SQL Server 2012 Developer Edition are same as previous versions. The Developer edition provides the same feature set as the Enterprise edition. However, it’s licensed per developer and can’t be used for production work. The Web edition is licensed only to hosting companies with a Services Provider License Agreement (SLPA).

So, this must have given you a good idea about editions and some of the features. Remember, there is cost associated with each version except if you are using evaluation purpose.