查詢sql查找所有未註冊的特定類的學生

Question

假設我有三個表Student，Class，Student_Class（鏈接表）。

Table:Student 
Student_ID 
FirstName 
LastName 

Table:Class 
Class_ID 
Class_name 

Table:Student_Class (Linking Table) 
StudentClass_ID 
Class_ID 
Student_ID 

給定一個特定的Class_ID，我想知道所有未註冊該特定班級的學生。

我試過以下，但它不起作用。可以說，我嘗試類ID = 3

SELECT DISTINCT Student.* 
FROM Student 
INNER JOIN Student_Class 
    ON Student.Student_ID = Student_Class.Student_ID 
WHERE ((NOT (Student_Class.Class_ID)= 3)) 

Answer 1

流量

1. 匹配所有學生，所有類

Student INNER JOIN Student_Class ON (Student.Student_ID = Student_Class.Student_ID)

拒絕學生特殊類別（例3）

(Student_Class.Class_ID <> 3)

查詢：

SELECT Student.* 
    FROM Student INNER JOIN Student_Class 
    ON (Student.Student_ID = Student_Class.Student_ID) 
WHERE (Student_Class.Class_ID <> 3); 

爲了讓他們沒有在任何課程的所有學生，請嘗試以下：

SELECT Student.* 
    FROM 
     (
     SELECT Student.* 
      , Student_Class.Class_ID 
      FROM Student LEFT JOIN Student_Class ON Student.Student_ID = Student_Class.Student_ID 
     WHERE ((Student_Class.Class_ID <> 3) OR (Student_Class.Class_ID IS NULL)) 
     ) Student LEFT JOIN Class ON Student.Class_ID = Class.Class_ID 
;

數據：

結果：

Answer 2

下面的查詢將顯示沒有參加一個或多個班級的所有學生，包括班級名稱。

SELECT Student.Student_ID, Student.FirstName, Student.LastName, 
Class.Class_ID, Class.Class_name 
FROM Class, Student 
WHERE NOT EXISTS 
(
SELECT * 
FROM Student_Class 
WHERE Student_Class.Student_ID = Student.Student_ID AND 
Student_Class.Class_ID = Class.Class_ID 

）