How does self join work internally in MySQL?

A self join in MySQL allows you to join a table to itself. This is useful when you want to compare rows within the same table. To perform a self join, you use a JOIN clause and give the table two different aliases, so you can differentiate between the two instances of the table.

Here’s a simple example of a self join:


            SELECT a.EmployeeID, a.Name AS EmployeeName, b.Name AS ManagerName
            FROM Employees a
            JOIN Employees b ON a.ManagerID = b.EmployeeID;