I'm trying to insert data from a table to a new table. I've written INSERT SELECT statements to accomplish this, but I'd like to INSERT new values only. For a few tables I've implemented some UPIs so I can basically only INSERT data by checking the corresponding key in the old table. Some new tables however, have a PK that's generated after inserting the data, meaning that there's no key from the old table to the new table, merely the data from the old table.
Any ideas how to check whether multiple columns already exist in the new database before inserting them?