The more I know, the more I know I DON'T know. I've toyed with the idea of getting some sort of sql certification (so I can be a better perl programmer, of course), but then that's a little sick and wrong.

Well, you have my sympathies... essentially there's an infinite amount of stuff we all need to learn in order to do the job right, so coming up with strategies to provisionally minimize what you need to learn is essential.

Myself, I would say that knowing your way around relational databases is a fairly fundamental, useful skill, and whether or not you bother with a "certification", it's not a bad direction to go in.