MySQL is a very fast, multi-threaded, multi-user and robust SQL (Structured Query Language) database server.
MySQL is a multiuser and fast SQL database server. MySQL has the following other editions available: MySQL for Linux, MySQL for FreeBSD and MySQL for Mac OS X.Download:

MySQL 是現在最流行的開放源代碼數據庫。絕大多數 PHP 網站的數據庫后臺都是采用這一數據庫。近日，MySQL AB 發布了 MySQL 5.0 系列的最新版本 5.0.41，添加了一些新功能并修正了大量 Bug。

Note:
When upgrading from versions of MySQL prior to 4.1.5, you must uninstall the existing version before installing a new version. Later versions may be upgraded with the installer without uninstalling.

Download: MySQL 5.0.41 (Page)
Download: Windows | Linux | FreeBSD | MAX OS X