I've also used databases with more than a 100 million rows in a single table and received realtime query performance in multi-table joins. And this is using Sql

I've also used databases with more than a 100 million rows in a single table and received realtime query performance in multi-table joins. And this is using Sqlite! No expensive DB licenses - but it was using a high-end SAN since we actually ran thousands of these multi-million row databases in parallel on the same server.