如何显示department_id，department_name和部门负责人？

Question

就我所知，输出应该是该部门的负责人在同一列的department_name下

SELECT department_id, department_name
FROM (SELECT d.department_id, d.department_name, 0 AS ent
      FROM departments d
UNION ALL
SELECT d.department_id, '--Department Head: '||e.last_name, 1 AS ent
FROM employees e INNER JOIN departments d ON e.manager_id = d.manager_id)
GROUP BY department_id, ent, department_name
ORDER BY department_id, ent, department_name;

我重写了这个问题，但我仍然不知道如何让每个分区的经理......

10  Administration
20  Marketing
20  --Department Head: Fay
30  Purchasing
30  --Department Head: Baida
30  --Department Head: Colmenares
30  --Department Head: Himuro
30  --Department Head: Khoo
30  --Department Head: Tobias
40  Human Resources
50  Shipping
50  --Department Head: Atkinson
50  --Department Head: Bissot
50  --Department Head: Bull

Department_ID              Department_name

10                         Administration

10                         Manager: Neena

20                         Marketing

20                         Manager: Harstrein

30                         Purchasing

30                         Manager: Popp