MySQL AB (founded 1995, acquired by Sun Microsystems 2008) was dual headquartered in Uppsala, Sweden and Cupertino, California, USA with offices in other countries (Paris, France; Munich, Germany; Dublin, Ireland; Milan, Italy; and Tokyo, Japan). The company is the creator and owner of MySQL, a relational database management system, as well as related products such as MySQL Cluster.
Together with Linux, Apache, and PHP, the MySQL Server forms one of the building blocks of the LAMP technology stack. The company claims a user base of over 5 million MySQL installations worldwide and over 10 million product downloads in 2004.
What generally distinguishes this "second generation" of companies, such as MySQL AB and Trolltech, from earlier "open source" business models is dual licensing — while the software may be made available under the provisions of some open source license, the software is, in fact, owned by the commercial companies who seek to derive revenues from selling traditional software licenses.
As an example, MySQL AB make MySQL available under the GPL at no charge, but sell it under other more traditional licenses to clients who do not find the GPL to be ideal for their purposes, such as inclusion of MySQL AB technology in a closed source product.
Other sources of revenue for MySQL AB are providing support and consulting, as well as training and certification for MySQL Server. Together with some additional services, MySQL also provide this as a subscription-based product called MySQL Enterprise, which is also resold by other companies such as Dell, HP, and Novell.