18th February 2021
Datasette 0.55 adds support for cross-database SQL queries. You can now run
datasette --crossdb one.db two.db and then run queries that join data from tables in both of those database files - see cross-database queries in the documentation for more details.
sqlite-utils 3.6 adds similar features: a
db.attach(alias, filepath) Python API method and
--attach alias filepath.db command-line option, both for attaching additional databases in order to execute cross-database queries.