SQL Queries Intro.
SQL statements are used to perform tasks such as updating data on a database, or retrieving data from a database. Some common relational database management systems that use SQL are: Oracle, Sybase, Microsoft SQL Server, Access, Ingres, and others. Some of these database systems will have extensions specific only to their system. However, the standard SQL commands such as "Select", "Insert", "Update", "Delete", "Create", and "Drop" are used with all these database systems.
or OnlineSQL Queries Intro.