MS SQL Server versions

SQL Server currently has many different versions. Below is a list of versions with features of each version.

Enterprise - the most advanced version with full functionality.
Standard - less features than Enterprise, use when you don't need to use advanced features.
Workgroup - suitable for large companies with many remote offices.
Web - designed specifically for web applications.
Developer - similar to Enterprise but only grant a single user to develop, test, demo. You can easily upgrade to the Enterprise edition without reinstalling.
Express - this version is only used at a simple level, up to 1 CPU and 1GB of memory, the maximum size of the database is 10GB.
Compact - free embedded into web application development environments. The maximum size of the database is 4GB.
Datacenter - big change on SQL Server 2008 R2 is the Datacenter Edition version. No memory limit and support for more than 25 installations.
Business Intelligence - Business Intelligence Edition was just introduced on SQL Server 2012. This version has the features of the Standard version and supports some advanced features of BI like Power View and PowerPivot but does not support advanced features. about availability as AlwaysOn Availability Groups .
Enterprise Evaluation - The SQL Server Evaluation Edition is a great choice to use all features and get a free installation of SQL Server for learning and development. This version has an expiration time of 6 months from the date of installation.