Andrew mentioned something super cool about what he and Anton have done with Beam SQL: it now implements a JDBC driver (via Calcite Avatica).
And since the sqlline client is tiny, it is just baked in. So you can java -jar the JDBC driver and run a little shell. But the shell only has the direct runner, and to make a nice experience for SQL users who don't want to deal with Java, there are some challenges.
I wrote up a really quick doc for brainstorming
Please lend you comments and expertise!