Write some backend Clojure code - the system interprets it as a SQL table, use it as a SQL table. Filter, join, aggregate, etc. Better yet, save the "code table" as a view -and in production your end-users can use it and never even know it's running code.
Disclaimer: This doesn't mean you need to know Clojure to use this tool at all. But if you want to dabble, it might take your "calculated fields" to a whole new level.
Hitting an HTTP API, doing some machine learning, anything that doesn't perfectly fit a SQL model - yet it gets treated as SQL data on the front-end.