How to copy data from certain tables of one database to another database?

Question

MySQL

There are DB1 and DB2
In DB2 there are tables A, B, C, D
In DB1 there are tables A, B, E, E
It is necessary to copy tables A and B from DB2 to DB1
How to do this in relation to MySQL?
How to do this in relation to PostgreSQL?
Where to dig?

Answer 1

And what is the difficulty? Export data from one database, upload to another. You can use postgres FDW.