Hi there!

I think the ideal way to transfer data from an old database to a new one is through a data pipeline. You should use tools like Apache NiFi or Talend to automate data migration. These tools help you to extract data from your old database and move it to your new one.

Another option is to write your SQL script, which selects the columns you are interested in from your old database and uploads them to your new database. It may take some time if there is a large range of records.

Apart from that, you can also try pg_dump, which is command-line tool that has inbuilt utility support to backup entire database or specific tables.

There are quite a few good tutorials on database backups and migrations, which you can find on StackOverflow and YouTube, and they will give you additional details on how to do it precisely.

Good luck with the migration!