SQL Server
Microsoft SQL Server is a relational database server, originally based on Sybase SQL Server and ported to OS/2 and Windows platforms. Microsoft currently support SQL Server 2008 R2, SQL Server 2008 and SQL Server 2005.
Available only on Windows platforms, SQL Server there are a number of different editions of SQL Server ranging from the free SQL Server Express aimed at competing with MySQL, Enterprise aimed at competing with Oracle, and DataCenter. There are also specialised editions like SQL Azure (cloud-based) and SQL CE (Compact Edition).
Transact-SQL (T-SQL)
Overview of Transact-SQL (T-SQL) - the procedural language supported by Microsoft SQL Server.