there is a possibility for Liquibase to generate sql file using updateSql. Also now offline mode is available but you need to provide changelog as a changelog table. But why it is not possible to generate an SQL file without any schema just having if clause to apply or skip migrations, for example:
mark migration_1 as completed
mark migration_2 as completed
So in this case we can generate SQL file without having any reference schemas. What do you think about this idea or, probably, it is already implemented?