Following some concern about compatibility between MySQL license and other Open Source languages (mostly PHP), MySQL has released an Exception to its licensing policy for non-GPL Free and Open Source Software (FOSS)

The issue started when the PHP group announced they were not releasing MySQL libraries with PHP 5, due to licensing conflicts. Soon after, other open source discussion forums raised similar concerns (and the Perl-Mysql mailing list among them.)

Thus MySQL seems to have given an answer to the worried ones.

IANAL, and therefore apply your oen judgement to the issue. As usual, many comments at the other site