I think the SQLite recursive queries are cool, but constructing them is very challenging for my brain. We use a couple of them for loading graphs of data on the client at $WORK and they’re all bamboozling to me. I’d rather write a Datalog variant - I wish I had differential-datalog for every data store I work with.
I explain a recursive CTE line by line here, perhaps you find it useful.
Yes I think this (graph in SQL) is borderline misuse of technology but it works! :)
The Mandelbrot Set and Sudoku solver are black magic to me.