多表关联查询

基本信息：

1.创建student和score表

CREATE TABLE student (
id INT(10) NOT NULL UNIQUE PRIMARY KEY ,
name VARCHAR(20) NOT NULL ,
sex VARCHAR(4) ,
birth YEAR,
department VARCHAR(20) ,
address VARCHAR(50)
);
创建score表。SQL代码如下：
CREATE TABLE score (
id INT(10) NOT NULL UNIQUE PRIMARY KEY AUTO_INCREMENT ,
stu_id INT(10) NOT NULL ,
c_name VARCHAR(20) ,
grade INT(10)
);

操作：

分别创建student表和score表：

create table student(id int(10) not null unique primary key,name varchar(20) not null,sex varchar(4),birth year,d
epartment varchar(20) not null,address varchar(50));
Query OK, 0 rows affected, 1 warning (0.04 sec)

 create table score(id int(10) not null unique primary key auto_increment,stu_id int(10) not null,c_name varchar(2
0),grade int(10));
Query OK, 0 rows affected, 3 warnings (0.03 sec)

2.为student表和score表增加记录

向student表插入记录的INSERT语句如下：
INSERT INTO student VALUES( 901,'张老大', '男',1985,'计算机系', '北京市海淀区');
INSERT INTO student VALUES( 902,'张老二', '男',1986,'中文系', '北京市昌平区');
INSERT INTO student VALUES( 903,'张三', '女',1990,'中文系', '湖南省永州市');
INSERT INTO student VALUES( 904,'李四', '男',1990,'英语系', '辽宁省阜新市');
INSERT INTO student VALUES( 905,'王五', '女',1991,'英语系', '福建省厦门市');
INSERT INTO student VALUES( 906,'王六', '男',1988,'计算机系', '湖南省衡阳市');
向score表插入记录的INSERT语句如下：
INSERT INTO score VALUES(NULL,901, '计算机',98);
INSERT INTO score VALUES(NULL,901, '英语', 80);
INSERT INTO score VALUES(NULL,902, '计算机',65);
INSERT INTO score VALUES(NULL,902, '中文',88);

操作：

向student表中填写数据：

mysql> INSERT INTO student VALUES( 901,'张老大', '男',1985,'计算机系', '北京市海淀区');
Query OK, 1 row affected (0.00 sec)mysql> INSERT INTO student VALUES( 902,'张老二', '男',1986,'中文系', '北京市昌平区');
Query OK, 1 row affected (0.00 sec)mysql> INSERT INTO student VALUES( 903,'张三', '女',1990,'中文系', '湖南省永州市');
Query OK, 1 row affected (0.01 sec)mysql> INSERT INTO student VALUES( 904,'李四', '男',1990,'英语系', '辽宁省阜新市');
Query OK, 1 row affected (0.01 sec)mysql> INSERT INTO student VALUES( 905,'王五', '女',1991,'英语系', '福建省厦门市');
Query OK, 1 row affected (0.00 sec)mysql> INSERT INTO student VALUES( 906,'王六', '男',1988,'计算机系', '湖南省衡阳市');
Query OK, 1 row affected (0.01 sec)

向score表中填写数据：

mysql> INSERT INTO score VALUES(NULL,901, '计算机',98);
Query OK, 1 row affected (0.01 sec)mysql> INSERT INTO score VALUES(NULL,901, '英语', 80);
Query OK, 1 row affected (0.01 sec)mysql> INSERT INTO score VALUES(NULL,902, '计算机',65);
Query OK, 1 row affected (0.00 sec)mysql> INSERT INTO score VALUES(NULL,902, '中文',88);
Query OK, 1 row affected (0.01 sec)