查询学生的学号和姓名mysql

多表查询：
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)
);

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);
INSERT INTO score VALUES(NULL,903, '中文',95);
INSERT INTO score VALUES(NULL,904, '计算机',70);
INSERT INTO score VALUES(NULL,904, '英语',92);
INSERT INTO score VALUES(NULL,905, '英语',94);
INSERT INTO score VALUES(NULL,906, '计算机',90);
INSERT INTO score VALUES(NULL,906, '英语',85);

3.查询student表的所有记录

select * from student;

4.查询student表的第2条到4条记录

select * from student where id>=902 and id<=904;

5.从student表查询所有学生的学号（id）、姓名（name）和院系（department）的信息

select id,name,department from student;

6.从student表中查询计算机系和英语系的学生的信息

select * from student where department='计算机系' or department='英语系';

7.从student表中查询年龄18~22岁的学生信息

select * from student where birth>=1998 and birth<=2002;

8.从student表中查询每个院系有多少人

select department,count(*) from student group by department;

9.从score表中查询每个科目的最高分

select c_name,max(grade) from score group by c_name;

10.查询李四的考试科目（c_name）和考试成绩（grade）

select  as name,si.c_name as c_name,si.grade as grade from student as li join score as si on( = si.stu_id)where name ='李四';

11.用连接的方式查询所有学生的信息和考试信息

select * from student as stu join score as sc on(=sc.stu_id);

12.计算每个学生的总成绩

select student.id as id,name,sum(grade) from student,score where student.id = score.stu_id group by id;

13.计算每个考试科目的平均成绩

select c_name,avg(grade) from score group by c_name;

14.查询计算机成绩低于95的学生信息

select * from student where id in(select stu_id from score where c_name='计算机' and grade<95);

15.查询同时参加计算机和英语考试的学生的信息

SELECT * FROM student WHERE id =ANY(SELECT stu_id FROM score WHERE stu_id IN 	(SELECT stu_id 	FROM score WHERE c_name='计算机') AND c_name='英语');

16.将计算机考试成绩按从高到低进行排序

SELECT stu_id, grade FROM score WHERE c_name= '计算机' ORDER BY grade DESC;

17.从student表和score表中查询出学生的学号，然后合并查询结果

select id from student union select stu_id from score;

18.查询姓张或者姓王的同学的姓名、院系和考试科目及成绩

SELECT student.id, name,sex,birth,department, address, c_name,grade FROM student, score WHERE(name 		LIKE '张%' OR name LIKE '王%')AND student.id=score.stu_id ;

19.查询都是湖南的学生的姓名、年龄、院系和考试科目及成绩

SELECT student.id, name,sex,birth,department, address, c_name,grade FROM student, score WHERE address LIKE '湖南%' AND student.id=score.stu_id;