1978. Employees Whose Manager Left the Company

• 문제
  
• 정답

SELECT e1.employee_id
FROM Employees e1
LEFT JOIN Employees e2
ON e1.manager_id = e2.employee_id
WHERE e1.salary < 30000 AND e2.employee_id IS NULL AND e1.manager_id IS NOT NULL
ORDER BY employee_id;

• 결과