employees.manager_id points to employees.id: a manager is an employee too. To show each employee with the name of their manager, join employees to itself.

SELECT e.name AS employee, m.name AS manager
FROM employees e
JOIN employees m ON e.manager_id = m.id;

The two aliases make two roles for the same table:

• e: the employee.
• m: the manager, the row whose id is the employee's manager_id.

A self join is an ordinary join. Every join kind works. Use LEFT JOIN to keep the employees without a manager.