在 MySQL 中连接最多 3 个表

Question

我的桌子是：

• student

  { Student_id 作为主键，firstName，lastName };

• teacher

  { Teacher_id 作为主键，firstName，lastName };

• course

  {course_id 作为主键，courseName，学分，teacher_id（来自教师表的外键）}

• class

  { class_id 作为主键，roomNumber，教师_id 来自教师的外键，course_id 来自课程的外键 }

• classStudent

  { Student_id 来自学生的外键，class_id 来自班级的外键 }

我想检索

courseName

、教师的名字和姓氏、特定学生 ID 的房间号。

我的数据库：

CREATE TABLE `student` 
(
    `student_id` int(10) NOT NULL,
    `firstName` varchar(20) NOT NULL,
    `lastName` varchar(20) NOT NULL,
    `phone_number` int(8) NOT NULL,
    `Email` varchar(40) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

CREATE TABLE `teacher` 
(
    `teacher_id` int(10) NOT NULL,
    `firstName` varchar(20) NOT NULL,
    `lastName` varchar(20) NOT NULL,
    `phone_number` int(8) NOT NULL,
    `Email` varchar(40) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

CREATE TABLE `course` 
(
    `course_id` varchar(10) NOT NULL,
    `Course_Name` varchar(20) NOT NULL,
    `Description` varchar(100) NOT NULL,
    `credits` int(1) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

ALTER TABLE `class`
    ADD PRIMARY KEY (`class_id`),
    ADD KEY `classTeacher` (`teacher_id`),
    ADD KEY `classCourse` (`course_id`);

ALTER TABLE `classstudent`
    ADD PRIMARY KEY (`class_id`,`student_id`),
    ADD KEY `studentClass` (`student_id`);

-- Constraints for table `class`
--
ALTER TABLE `class`
    ADD CONSTRAINT `classCourse` 
        FOREIGN KEY (`course_id`) REFERENCES `course` (`course_id`) 
            ON UPDATE CASCADE,
    ADD CONSTRAINT `classTeacher` 
        FOREIGN KEY (`teacher_id`) REFERENCES `teacher` (`teacher_id`);

--
-- Constraints for table `classstudent`
--
ALTER TABLE `classstudent`
    ADD CONSTRAINT `classstudent_ibfk_1` 
        FOREIGN KEY (`class_id`) REFERENCES `class` (`class_id`),
    ADD CONSTRAINT `studentClass` 
        FOREIGN KEY (`student_id`) REFERENCES `student` (`student_id`);

ALTER TABLE `classstudent`
    ADD PRIMARY KEY (`class_id`,`student_id`),
    ADD KEY `studentClass` (`student_id`);

我也是堆栈溢出的新手，所以请告诉我是否有关于我的问题的任何说明。

Answer 1

Select  course.courseName, teacher.firstName, teacher.lastName, class.roomNumber
from student
 inner join classStudent 
on student.student_id=classStudent.student_id
 inner join class
on classStudent.class_id = class.class_id
Inner join course
On class.course_id = course.course_id
Inner join teacher
On course.teacher_id = teacher.teacher_id
Where student.student_id = ?