MySQL is a relational database management system (RDBMS)[1] which has more than 11 million installations.[2] The program runs as a server providing multi-user access to a number of databases.

MySQL is owned and sponsored by a single for-profit firm, the Swedish company MySQL AB, now a subsidiary of Sun Microsystems,[3] which holds the copyright to most of the codebase. The project's source code is available under terms of the GNU General Public License, as well as under a variety of proprietary agreements.

"MySQL" is officially pronounced /maɪˌɛskjuːˈɛl/[4] (My S Q L), not "My sequel" /maɪˈsiːkwəl/. This adheres to the official ANSI pronunciation; SEQUEL was an earlier IBM database language, a predecessor to the SQL language.[5] The company does not take issue with the pronunciation "My sequel" or other local variations.[4]