加入的SQL问题

Question

我有三张桌子，上面有学生，员工和学生。 Employees和Students中的“City”列是一个整数，指的是存储很多城市的Table City。

现在，我想要一份员工和学生表中每个人的列表，其中包含该人所在的城市。

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

我还建议更改一些字段名称：

• 表格学生：将Student重命名为Name
• 表格学生：将City重命名为CityID
• 表员工：将City重命名为CityID

Answer 2

以下内容如何：

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