php sql join together multiple tables from different databases

Question

I have 3 databases, and now I need to join several tables from each one of them into a singel query. How do I do this?

This is my connection:

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Answer 1

You will need a user that has access to all three databases.

You will JOIN them together by specifying full table name, something like this:

SELECT * FROM database_1.logs AS d1 LEFT JOIN database_2.users AS d2 
  ON d1.username = d2.username ORDER BY d1.timestamp DESC LIMIT 10