This advanced SQL exercise is part of the book: Advanced SQL – Practical Techniques and Use-Cases, which includes 100 day-to-day SQL challenges (and solutions), need-to-know advanced features, and key concepts.
 

“Northern Wind” company , which markets winter clothing, manages the following tables :

Employees table – Each row on this table indicates the employee name, number, department number, and manager number. For example, Moshe (employee no. 1) is the manager of Yossi, Tomer, and Ronen.

CREATE TABLE employees
(emp_id int,
emp_name varchar(25),
dep_id int,
manager_id int)

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