Answer
Employee counts per department use COUNT and GROUP BY. • COUNT(*) counts employee rows in each group. • An inner query omits departments with no employees. • Use a LEFT JOIN from departments to include zero-count departments.
💡 SQL Example
SELECT department_id, COUNT(*) AS employee_count FROM employees GROUP BY department_id;
Result
One employee count per represented department
⚡ Quick Revision
Group employee rows by department and count each group.