You will have to create a database link to read or write to a table located in another database. Below is an example of creating a database link:

CREATE DATABASE LINK mydblink 
CONNECT TO remote_db IDENTIFIED BY password
USING '(DESCRIPTION=
(ADDRESS=(PROTOCOL=TCP)(HOST=yourhost)(PORT=1521))
(CONNECT_DATA=(SERVICE_NAME=yourservice_name))
)';

Now you can select the rows from the remove database table as follows:

Select * from myxyz@mydblink;