It’s miserable when your starting point is the default js implementation for the executor, but if you write your own executor you have a lot of freedom to do cool stuff.

I’ve built a graphql interface here https://subzero.cloud on top of the powerful rest interface of https://postgrest.com which in turn sits on top of postgresql.

The end result is you define your tables/views/functions in sql and on the other end you get rest+graphql api to your data