Hey there, I’m a committer to the Apache Superset project and am friendly with the Trino community as well!
As long as your Trino cluster & config is setup to query both BigQuery and MySQL, it should “Just Work ™” out of the box. We actually ran an event where we join data from Pinot and Mongo and you basically just need to get the schema + table syntax right!
Some sample syntax:
SELECT *
FROM mongo.transport.flight
JOIN pinot.galaxy.covid_cases
ON .....
Here’s the recording from an event: Visualizing MongoDB and Pinot Data Using Trino (demo starts at around 32nd minute).