Medium
LEFT JOIN
Department Employee Coverage
Show all departments and their employee count, including departments with no employees. Return columns: department_name, employee_count. Order results by: d.id.
Preparing the interactive SQL workspace...
Challenge overview
What you will practice
Show all departments and their employee count, including departments with no employees. Return columns: department_name, employee_count. Order results by: d.id.
- Difficulty
- Intermediate
- SQL concept
- LEFT JOIN
Public schema and sample data
departments
| id INTEGER | name TEXT | budget REAL | location TEXT |
|---|---|---|---|
| 1 | Engineering | 1500000 | New York |
| 2 | Marketing | 800000 | London |
| 3 | Sales | 600000 | Chicago |
employees
| id INTEGER | first_name TEXT | last_name TEXT | email TEXT | department_id INTEGER | salary REAL | hire_date TEXT | manager_id INTEGER |
|---|---|---|---|---|---|---|---|
| 1 | Alice | Johnson | alice@corp.com | 1 | 95000 | 2019-03-15 | NULL |
| 2 | Bob | Smith | bob@corp.com | 1 | 85000 | 2020-06-01 | 1 |
| 3 | Carol | Williams | carol@corp.com | 2 | 72000 | 2018-11-20 | NULL |