这篇文章主要介绍“MySQL如何创建多对多和一对一关系”，在日常操作中，相信很多人在MySQL如何创建多对多和一对一关系问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”MySQL如何创建多对多和一对一关系”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
一、创建多对多
1.学生表
create table students (
id int not null primary key auto_increment,
name varchar(45) not null
)engine=innodb default charset=utf8;
2.课程表
create table courses (
id int not null primary key auto_increment,
name varchar(45) not null
)engine=innodb default charset=utf8;
3.中间表
create table stu_cour (
id int not null primary key auto_increment
course_id int not null,
stu_id int not null,
constraint cour foreign key(course_id) references courses(id),
constraint stu foreign key(stu_id) references students(id)
)engine=innodb default charset=utf8;
4.插入数据
insert into students values (0,"小王");
insert into students values (0,"小宋");
insert into students values (0,"小李");
insert into courses values (0,"语文");
insert into courses values (0,"数学");
insert into courses values (0,"英语");
insert into stu_cour values (0,1,1);
insert into stu_cour values (0,1,2);
insert into stu_cour values (0,1,3);
insert into stu_cour values (0,2,1);
insert into stu_cour values (0,2,3);
insert into stu_cour values (0,3,2);
insert into stu_cour values (0,3,3);
5.查询学生1选了哪些科目
SELECT courses.id,courses.name FROM courses
INNER JOIN stu_cour ON stu_cour.course_id=courses.id
INNER JOIN students ON students.id= 1
and students.id = stu_cour.stu_id;
6.查询id=2数学被谁选了
SELECT students.name FROM students
INNER JOIN stu_cour ON stu_cour.stu_id =students.id
INNER JOIN courses ON courses.id= 2
and stu_cour.course_id = courses.id;
二、MySQL 创建一对一关系
1.一对一
创建用户表：
CREATE TABLE users (
id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(50) NOT NULL
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
用户信息表：
CREATE TABLE users_info (
id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
age int NOT NULL,
phone varchar(11) NOT NULL,
user_id int not null,
constraint user_info foreign key(user_id) references users(id)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
2.插入数据
insert into users values (0,"小王");
insert into users values (0,"小宋");
insert into users_info values (0,12,'13812345678',1);
insert into users_info values (0,14,'13812345679',2);
查询人的全部信息：
select * from users inner join users_info on
users_info.user_id =users.id;
到此，关于“MySQL如何创建多对多和一对一关系”的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注天达云网站，小编会继续努力为大家带来更多实用的文章！