MySQL Enterprise Unlimited is designed for companies with existing site licences for Oracle, Microsoft SQL Server, Sybase and IBM DB2.
A survey last year of the Independent Oracle Users Group showed that a third of its membership also used MySQL.
"Open source has the ability to disrupt traditional enterprise software pricing due in large part to advantages in distribution and volume," said Stephen O'Grady, principal analyst at RedMonk.
"MySQL is attempting to prove as much with its latest site-wide agreements, which allow customers to support every database across their enterprise at a fraction of the traditional cost."
MySQL Enterprise subscription consists of MySQL Enterprise Server Software, MySQL Network Monitoring & Advisory Services and Premier Enterprise-class Production Support including 24x7 telephone, Knowledge Base and web support.