MySQL is a free, open source SQL database that started in 1995. It also has proprietary licensing available, which includes support and maintenance. Sun Microsystems bought MySQL in 2008, which was then acquired by Oracle in 2010. MySQL is commonly used in conjunction with PHP web applications. MySQL is a great choice for organizations that need a good RDMS but have a tight budget.

The advantages of MySQL are that it's available for free, it offers a lot of functionality for system and database administrators, it's easy to use and implement, and it's fast and stable. 

The disadvantages of MySQL are that while support is available, it's not free. Also, since it's under Oracle, not all features are free, including paid-for options, such as enterprise monitoring, backup, high availability, scalability, and security.