Lion Server no longer includes MySQL, and instead is bundled with PostgreSQL. This is a major change, which personally frustrates me to no end since I have developed dozens of websites for Mac servers that rely on MySQL databases.

According to Apple Knowledgebase article HT4828, if you upgrade/migrate a server that was running to MySQL to Lion Server, the MySQL binaries and database will be copied and preserved, but you then have to manually upgrade the MySQL to 5.1, then to 5.5… and currently Oracle doesn’t have complied Mac OS 10.7 binaries for either version.

If you have a Mac server that relies on a MySQL, for the time being don’t even consider upgrading to Lion Server.