I have many SpatiaLite layers, each in a separate database. I want to load all these SpatiaLite layers into a single database. How can this be done?
If they are SpatiaLite layers, they are already in a database. If you meant that they are in different databases (which you did not stated in your original question), you can use the DB Manager plugin, just expand your SpatiaLite connections in the
Tree and drag & drop the SpatiaLite layers you want to import from each DB to your target DB.