Connect two remote oracle databases as a schemas on each other
Several issues, in no particular order.
Your SELECT syntax is wrong. To select a table from another database the syntax is
select some_columns from remote_table@remote_db;

Note the &quot;@remote_db&quot;.  Here 'remote_db' refers to an entry in the local database's tnsnames.ora file, which in turn resolves to the remote db in question.   CORRECTION:  Here 'remote_db' is the name of the database link.
Second, you say you have no permission to create a db link. Well, someone is going to have to create one.  That is the mechanism by which one database queries another. Period. Full stop.
Third, you say you find no db links when you query ALL_LINKS.  The name of the view is ALL_DB_LINKS.  And that only shows the links that the current user has permissions on.  If you want to see all links in the database, you query DBA_DB_LINKS, as a user that has permissions to query that view.  Plus, I see nothing in your question description that would cause me to suspect that there indeed are any db links.