mysql修改中间表的数据

CREATE TABLE students (
    student_id INT PRIMARY KEY,
    student_name VARCHAR(100)
);

CREATE TABLE courses (
    course_id INT PRIMARY KEY,
    course_name VARCHAR(100)
);

CREATE TABLE student_courses (
    student_id INT,
    course_id INT,
    PRIMARY KEY (student_id, course_id),
    FOREIGN KEY (student_id) REFERENCES students(student_id),
    FOREIGN KEY (course_id) REFERENCES courses(course_id)
);

INSERT INTO students (student_id, student_name) VALUES (1, 'Alice');
INSERT INTO students (student_id, student_name) VALUES (2, 'Bob');

INSERT INTO courses (course_id, course_name) VALUES (101, 'Math');
INSERT INTO courses (course_id, course_name) VALUES (102, 'Science');

INSERT INTO student_courses (student_id, course_id) VALUES (1, 101);
INSERT INTO student_courses (student_id, course_id) VALUES (1, 102);
INSERT INTO student_courses (student_id, course_id) VALUES (2, 101);

-- 删除原来的关联
DELETE FROM student_courses WHERE student_id = 1 AND course_id = 101;

-- 插入新的关联
INSERT INTO student_courses (student_id, course_id) VALUES (1, 103); -- 假设 History 的 course_id 是 103