Yeah the final product uses SQL backend. (SQLite at the moment) . The idea is the user wouldn't have to mess with that, although some concepts such as grouping and aggregations map nearly 1-1 with SQL concepts, you just click/select what you want, and with some experimenting it should become apparent what was going on (I hope)
Still more work to be done on the team stats, I could add more filter types, allow, custom stats, etc. but right now I find working on the event files more interesting. Like I would want to see all at-bats Babe Ruth had vs. Walter Johnson, something like that.
There are resources like Chadwick and Boxball, might be faster to get certain things but I thought it would be fun to process the raw data myself, as well as have max flexibility to extract what I want