篩選並根據平均值計算

Question

我的問題是：列出所有工資高於平均工資的員工，並顯示差異有多大。

SELECT staffname 
FROM staff 
WHERE salary >= (SELECT Avg(salary) 
        FROM staff) 
     AND (SELECT Max(salary) AS Max_Salary, 
        Avg(salary) AS Avg_Salary 
      FROM staff 
      WHERE salary = max_salary - avg_salary) 

工資是高於平均工資是走出來就好了，但我不能拿出多少是不同的。

Answer 1

SELECT staffname, staff.salary - avg.salary 
FROM staff, (SELECT AVG(salary) salary FROM staff) avg 
WHERE staff.salary > avg.salary 

Answer 2

Select Count(*), (Select Avg(Salary) From Staff) 
From Staff 
Where Salary > (Select Avg(Salary) From Staff);