Find the ids of the departments where any manager is managing 4 or more employees.
SELECT DISTINCT department_id FROM employees GROUP BY department_id ,  manager_id HAVING COUNT(employee_id)  >= 4
SELECT DISTINCT department_id FROM employees GROUP BY department_id ,  manager_id HAVING COUNT(employee_id)  >= 4
[{'DEPARTMENT_ID': 30}, {'DEPARTMENT_ID': 50}, {'DEPARTMENT_ID': 60}, {'DEPARTMENT_ID': 80}, {'DEPARTMENT_ID': 100}]