Self-Join Employee Hierarchy | Dataford Interview Questions

Write an SQL query to perform a self-join on an employee hierarchy table.

Use the table to associate each employee with their direct manager, while retaining the top-level employee who has no manager.

Output

employee_hierarchy

Column	Type	Description
employee_idPK	INT	Unique identifier for the employee
employee_name	VARCHAR(100)	Employee's full name
department	VARCHAR(100)	Employee's department
manager_id	INT	Identifier of the employee's direct manager

Your question is Self-Join Employee Hierarchy. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Write an SQL query to perform a self-join on an employee hierarchy table.

Use the table to associate each employee with their direct manager, while retaining the top-level employee who has no manager.

employee_hierarchy

Column	Type	Description
employee_idPK	INT	Unique identifier for the employee
employee_name	VARCHAR(100)	Employee's full name
department	VARCHAR(100)	Employee's department
manager_id	INT	Identifier of the employee's direct manager

Your question is Self-Join Employee Hierarchy. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.