Another exercise that's fun is playing with Sqlite virtual tables and/or the Sqlite VFS layer.
Virtual tables: https://www.sqlite.org/draft/vtab.html
A simple example of using VFS to add a useful feature: https://github.com/Metalnem/sqlite-vfsdemo
Virtual tables: https://www.sqlite.org/draft/vtab.html
A simple example of using VFS to add a useful feature: https://github.com/Metalnem/sqlite-vfsdemo
https://www.sqlite.org/lang_attach.html
If you use a GUI front-end like SQLiteStudio (https://sqlitestudio.pl/), attaching databases is ridiculously easy to do. Just add the database name from the left column in front of the table or table.column label for the database you want to reference. Most SQLite GUI's will do the attach command for you internally.
I add the database name to my queries instinctively now in SQLiteStudio, so that no matter which DB is currently in focus/opened the query runs on the one I intended it to run on.