MySQL
MySQL is a popular cross-platform Database Management System. It is commonly used in WAMP, MAMP and LAMP environments (Windows|Macintosh|Linux/Apache/MySQL/PHP) and utilizes the SQL syntax for scripting queries.
MySQL's primary use is in storing data for websites that need to have dynamically generated content. The popularity of PHP, which has most of its distributions pre-compiled with support for accessing MySQL databases, makes MySQL a popular choice for many developers. Until recently it was not seen as a serious contender against MSSQL and Oracle, but with the recent additions of an enterprise level server with clustering support it has started gaining acceptance as a robust database server solution that large businesses can rely on.
MySQL is primarily developed by the Swedish for-profit company MySQL AB