Joining same table vs Joining different table in Mysql? Is there any difference between joining same table again and again and joining different tables? Internally it is just another join. But will it make a difference? Like If I join same table again and again only index of that table alone will reside in memory. So is there any other things like this? Or Will joining same table again and again degrade performance?
As you suspect, a JOIN does not care whether it is the same table or another table.  (Of course, you will have to use aliases to distinguish them.)

Would you care to show us some SQL; the question seems like a rather odd choice.