如何顯示部門（一次）以及在該部門工作的所有員工的列表？

Question

對於架構epartments(department_id, department_name) employees(last_name, department_id, salary)
我想要顯示的department_id, department_name, count(employees),avg(salary),last_name,salary
我曾嘗試使用下面的查詢

SELECT d1.department_id,d1.department_name,d1."count",d1."avg",e.last_name,e.salary 
FROM employees e 
INNER JOIN (SELECT d.department_id,d.department_name,count(e.last_name) AS "count",round(avg(e.salary),2) AS "avg" 
       FROM employees e,departments d 
       WHERE e.department_id=d.department_id 
       GROUP BY d.department_id,d.department_name) d1 
    ON e.department_id=d1.department_id; 

雖然顯示正確的輸出它不是我想要的格式。 上面的查詢給出的

90 Executive 3 19333.33 King 24000 
90 Executive 3 19333.33 Kochhar 17000 
90 Executive 3 19333.33 De Haan 17000 
60 IT   3 6400  Hunold 9000 
60 IT   3 6400  Ernst 6000 
60 IT   3 6400  Lorentz 4200 
50 Shipping 5 3500  Mourgos 5800 

輸出，而應該像

90 Executive 3 19333.33 King 24000 
           Kochhar 17000 
           De Haan 17000 
60 IT   3 6400  Hunold 9000 
           Ernst 6000 
           Lorentz 4200 
50 Shipping 5 3500  Mourgos 5800 

Answer 1

如果你真的想顯示類似''，而不是在查詢這些數據，我想你可以使用ROW_NUMBER()爲像這樣：

CASE 
    WHEN (ROW_NUMBER() OVER (PARTITION BY d1.department_id 
          ORDER BY d1.department_id)) = 1 THEN 
     d1.department_id 
    ELSE 
     Null 
END 

爲列：d1.department_id，d1.department_name，d1."count"，d1."avg"。