Joining Saved questions throwing an error

I'm trying to JOIN two questions in meta. Basically I have two MySQL databases. Each database has pretty much identical structure in terms of tables and columns. In the first question I'm simply doing a basic question where I get a full list of users from one single table and I save the question. For the second question I do the same and the matching column between both questions is "email". Once I join the questions I'm getting " There was a problem with your question

Most of the time this is caused by an invalid selection or bad input value. Double check your inputs and retry your query." and in addition I get this error "Card 2740 does not exist.". I have no clear idea what might be the reason but if someone has experienced the same problem it will be great to get some feedback. Thank you!

Hey rmivanov

You often get that error when you’re either trying to join tables from two different data sources (databases), or made an underlying change to the schema in your database, and haven’t adjusted your questions in Metabase to reflect this change.

Thanks

Hey @Filmon , that's exactly the case . I'm trying to join tables from two different data sources. Do you mean that this is still not possible even with pre-saved questions? Thanks!

Hey rmivanov

Correct. That's something that's not possible at the moment.

Normally in these cases you'd use a wrapper like Trino to connect multiple databases outside of Metabase.

Thanks