MySQL database client (metapackage depending on the latest version) This is an empty package that depends on the current "best" version of mysql-client (currently mysql-client-5.0), as determined by the MySQL maintainers. Install this package if in doubt about which MySQL version you need. That will install the version recommended by the package maintainers. MySQL is a fast, stable and true multi-user, multi-threaded SQL database server. SQL (Structured Query Language) is the most popular database query language in the world. The main goals of MySQL are speed, robustness and ease of use.