1.MySQL多表查询练习题

数据库表

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) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

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)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;


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');

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);

1.查询student表的所有记录

 select * from student

2.查询student表的第2条到4条记录

select * from student  limit 1,3

3.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

4.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'

5.从student表中查询年龄18~22岁的学生信息

 select * from student  where birth between 1998 and 2002

6.从student表中查询每个院系有多少人

select department,count(1) from student  group by department

7.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

8.查询李四的考试科目（c_name）和考试成绩（grade）

 select c_name,grade from score,student where student.id=score.stu_idand name='李四'

9.查询所有学生的信息和考试信息

select * from score,student  where score.stu_id=student.id

10.计算每个学生的总成绩

select sum(grade),name from score left outer join student on  sttudent.id=score.stu_id group by name

11.计算每个考试科目的平均成绩

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

12.查询计算机成绩低于95的学生信息

 select student.*,score.grade from student

                 left outer join score  on student.id=score.stu_id
                 where grade<95 and c_name='计算机'

13.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 in(select s1.stu_id from score s1 left outer join score s2 on s1.stu_id=s2.stu_id where s1.c_name='计算机' and s2.c_name='英语')

14.将计算机考试成绩按从高到低进行排序

select grade from score where c_name='计算机' order by grade desc

15.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 stu_id,c_name,name,department,grade from score,student

        where stu_id in(select id from student where name like'张%' or '王%') and stu__id=student.id

16.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 name,birth,department,c_name,grade from student

           left outer  join score on student.id=score.stu_id where student.id in (select id fromm student where address like '湖南%')