Jay Allen has found what he calls the world's smallest MySQL admin script and has posted about it to his CodingThis.com blog - Adminer.

I’ve spent years using phpMyAdmin (much to my chagrin). And I’ve recently warmed up to MySQL Workbench. But it wasn’t until this week that I stumbled across Adminer, a single-file PHP application for MySQL administration. It’s hard not to be impressed by Adminer, which is both devilishly simple and elegantly designed. The file downloads as adminer-2.3.2.php; save it as index.php in a folder named adminer, then navigate to http://servername.com/adminer/. Supply the name of your MySQL server (adding a colon if it’s hosted on a non-standard port), your username, and password, and you’re off!

He includes a few screenshots of the interface to create tables and manage them. If you've used the phpMyAdmin interface, you'll find a lot of things that are familiar in Adminer. If you're interesting in grabbing the latest source, you can pull it from SourceForge.