You can try Data Blending (search Tableau Help for it), but it is not the same as a database join and there are limitations. It usually works well with simple views, but causes headache with more complex ones.
When you say two different instances, do you mean two different connection names? If yes, then as there is no mechanism in Tableau to blend two data sources into one connection, you can try to do some magic within Oracle and bring both objects into one instance somehow.
Hello Dimitri Blyumin,
Thanks for your response.
Please correct me if my understanding is wrong.
Are you saying that, We cannot merge columns from 2 differenet oracle instances(connection) into single tableau worksheet ?
It depends on how you define merge.
Tableau sheet can only have one connection, but it can be blended with another connection. Results may vary, depending on your data and what view you want.
If your oracle user has the proper grants, than you can simply create a database link and use a single select to query and join both tables