If you're looking for a really light SQL library for Clojure, I recommend yesql: https://github.com/krisajenkins/yesql
I'm talking about the kind of stuff something like Korma or SQLAlchemy enable where you build up a query to be executed dynamically based on, for example, user filters.
I haven't need anything like that on any of my pet projects so I've been deliriously happy with Yesql. But, while working on those pet projects I do often find myself thinking about whatever I'm doing in my day job and I haven't come up with a good way to support composability within the context of Yesql. I would love to see a solution to that.