Check out: SequelSphere <http://www.sequelsphere.com>
that has great support for SQL. I am apart of SequelSphere, and am just
now beginning to look at how SequelSphere could be integrated with Node.js.
We created SequelSphere to be more of a Client-Side database, but I don't
see why it couldn't work fine on Node.js as well. It persists it's data to
localStorage and IndexedDB, so I don't know if that is a problem with
Node.js, or if there would need to be a different persistence mechanism.
Engine, SequelSphere may work well for you. Feel free to provide feedback