SQL interview question: Employees Without a Manager
Employees Without Managers
HR discovered some employee records have NULL in the manager_id field, indicating either top executives or data quality issues.
Find all employees who don't have a manager assigned (manager_id IS NULL).
Return employee_id, name (full name), and department_id. These are top executives.
Skills: NULL handling with IS NULL operator
Tables
employees 37 rows
- id integer PK
- first_name text
- last_name text
- email text
- department_id integer → departments
- salary integer
- hire_date text
- manager_id integer → employees
- title text
| id | first_name | last_name | department_id | salary | hire_date | manager_id | title | |
|---|---|---|---|---|---|---|---|---|
| 1 | Alice | Chen | [email protected] | 1 | 250000 | 2015-01-15 | NULL | CEO |
| 2 | Robert | Martinez | [email protected] | 2 | 180000 | 2016-03-20 | NULL | CEO |
| 3 | Sarah | Johnson | [email protected] | 1 | 150000 | 2017-06-10 | 1 | VP Engineering |