create table student

(

    id int primary key ,  #主键约束

    name varchar()  ,  #唯一约束

    age int NOT NULL, #非空约束

    sex varchar() ,

    address varchar() default '广西'  #默认约束

) ;

插入数据：

insert into student values(
-> '13408400106',
-> '龙永震',
-> '24',
-> '男',
-> '广西');

create table score

(

    id int primary key ,

    sid int ,             #上个表的主键

    china int ,

    history int,

    english int,

    constraint FK_sid foreign key(sid) references student(id)  #通过外键创建链接

) ;

插入数据：
insert into score values( '120491','13400106' , '100',  '100', '100');

#select student.id,student.name,student.age,student.sex,student.address,score.id,score.china,score.history,score.english from student inner join score;

+----------+-----------+-----+------+---------+--------+-------+---------+---------+
|   id     |  name | age | sex | address | id    | china | history | english |
+----------+-----------+-----+------+---------+--------+-------+---------+---------+
| 13400106 | 龙永震 | 24  | 男  | 广西    | 120491 | 100   | 100     | 100     |
+----------+-----------+-----+------+---------+--------+-------+---------+---------+

select * from score inner join student ;

+--------+----------+-------+---------+---------+----------+-----------+-----+------+---------+

| id     | sid      | china | history | english | id       | name      | age | sex  | address |

+--------+----------+-------+---------+---------+----------+-----------+-----+------+---------+

|  |  |    |      |      |  | 龙永震    |   | 男   | 广西    |

+--------+----------+-------+---------+---------+----------+-----------+-----+------+---------+