As you plan your installation, you need to know which SQL Server editions exist so that you can choose the most appropriate edition. Microsoft supports the following editions of SQL Server 2012:
Express Edition – The lightweight version of SQL Server, designed for use by application developers. For this reason, the product includes the basic Express Manager (XM) program and supports Common Language Runtime (CLR) integration and native XML. Also, you can download SQL Server Management Express for SQL Server Express to easily manage a database. SQL Server Express is available as a free download at http://msdn.microsoft.com/express.
Workgroup Edition – Designed for small businesses and for use at the department level. This edition provides relational database support without the business intelligence (BI) and high-availability capabilities. It supports up to two processors and a maximum of 2GB of RAM.
Standard Edition – Designed for small and medium-sized businesses. It supports up to four processors as well as 2TB of RAM and includes the full range of BI functionality, including Analysis Services, Reporting Services, and Integration Services. This edition does not include many enterprise-based features from Enterprise Edition (such as failover clustering, for instance).
Web Edition – Designed for web-hosting providers. In addition to the Database Engine, this edition includes Reporting Services. It provides support for up to four processors and 2TB of RAM
Enterprise Edition – The special form of the SQL Server system that is intended for time-critical applications with a huge number of users. In contrast to Standard Edition, this edition contains additional features that can be useful for very highend installations with symmetrical multiprocessors or clusters. The most important additional features of Enterprise Edition are data partitioning, database snapshots, and online database maintenance.
Developer Edition – Allows developers to build and test any type of application with SQL Server on 32- and 64-bit platforms. It includes all the functionality of Enterprise Edition, but is licensed only for use in development, testing, and demonstration. Each license of Developer Edition entitles one developer to use the software on as many systems as necessary; additional developers can use the software by purchasing additional licenses. For rapid deployment into production, the database system of Developer Edition can easily be upgraded to Enterprise Edition.
Datacenter Edition – A new edition as of SQL Server 2008 R2 that is designed to support the highest level of scalability. It doesn’t have any memory limitations, and you can create up to 25 instances. It also supports a maximum of 256 logical processors.
Parallel Data Warehouse Edition – Dedicated to data warehousing and supports data warehouse databases from 10TB to 1PB (petabyte). To manage such huge databases, it uses MPP (massively parallel processing) architecture, introduced by Microsoft with its High Performance Computing (HPC) Windows operating systems.