Liquibase changeset as target/source for diffs and edits

I’m looking at liquibase as means to transform my sql schema/data during a migration. 

It would be handy if liquibase allowed the database change set to be a database itself, performing changeset operations on the changesets :slight_smile:  This would allow a changeset to be modified before application to a db migration/update.

Another useful feature that I’m looking for seems missing: the ability to only grab data from specific tables.

Is this in any way possible right now?  Or is this some wishing thinking?