加入SQL的問題

Question

我有三張學生，員工和學生的表格。 「員工和學生」中的「城市」一欄是一個整數，指的是城市中有許多城市的表格城市。

現在我想每個人在這個城市的人位於進員工和學生表的列表。

例如：

 
    Name    | City 
    --------------------------------- 
    James (Employee) | London 
    Jesus (Student) | London 
    Daniel (Employee) | Manchester 

Answer 1

SELECT Name, 'Employee' AS 'Role', c.City 
FROM Employees AS e 
INNER JOIN Cities AS c ON e.City = c.id 
UNION ALL 
SELECT Student, 'Student' AS 'Role', c.City 
FROM Students AS s 
INNER JOIN Cities AS c ON s.City = c.id 

我還建議改變一些字段名：

• 學生表：重命名Student到Name
• 學生表：重命名City到CityID
• 表員工：重命名City到CityID

Answer 2

如何如下：

SELECT e.Name + '(Employee)', c.City 
FROM Employees e 
INNER JOIN Cities c ON e.City = c.id 
UNION ALL 
SELECT s.Student + '(Student)', c.City 
FROM Students s 
INNER JOIN Cities c ON s.City = c.id