MySQL “kind of sort of (not really) changes its license model”. Until recently, MySQL was licensed under GPLv2 or later, but they have changed their license to be GPLv2 only. This may sound like a small change, but it is a significant (and smart change). Anyone licensed under GPLv2 or later will automatically convert to the GPLv3 when it is released. This gives MySQL the option to decide whether (or not) to move to the GPLv3, instead of automatically converting upon release of GPLv3. MySQL will have the opportunity to review the final version of the GPLv3 license and make an informed decision about which license makes the most sense for MySQL's business needs.
Not every company (or project / organization) can change their license at will:
MySQL owns the copyright to its database code so can change the license any time it likes (and indeed offer the software under dual licenses). While the company is not ruling out a change to GPL v3 once it is completed, it is hedging its bets in case it does not like the results.” (Quote from Matthew Aslett on Computer Business Review Online)