【SQL测试题】SQL编程测试

现有以下几张表

教师表

 课程表

学生表 

选课表 

 问题描述及解答

1.查询"01"课程比"02"课程成绩高的学生的信息及课程分数

select student.* from score s1,score s2,student where student.s_id=s1.s_id and student.s_id=s2.s_id and s1.c_id="01" and s2.c_id="02" and s1.s_score>s2.s_score

2. 查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩

select t1.s_id,t1.s_name,avg(s1.s_score) from score s1,student t1 where t1.s_id=s1.s_id group by s1.s_id having avg(s1.s_score)>=60

3. 查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩 (包括有成绩的和无成绩的)

select * from(select t1.s_id,t1.s_name,avg(s1.s_score) avg_score from score s1 right join student t1 on t1.s_id=s1.s_id group by s1.s_id) t where t.avg_score<60 or t.avg_score is null

4. 查询学过"张三"老师授课的同学的信息

select * from student s1,score s2,course c,teacher t where t.t_name="张三" and t.t_id=c.t_id and c.c_id=s2.c_id and s2.s_id=s1.s_id

5. 查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩

select s1.s_id,s1.s_name,count(s1.s_id),sum(c.s_score) from student s1 left join score c on s1.s_id=c.s_id group by s1.s_id

6. 查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息

select * from student s1,score s3,score s2 where s1.s_id=s2.s_id and s1.s_id=s3.s_id and s2.c_id="01" and s3.c_id="02"

7. 查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息

select * from student s1 left join score s2 on s1.s_id=s2.s_id and s2.c_id="01" left join score s3 on s1.s_id=s3.s_id and s3.c_id="02" where s2.c_id="01" and s3.c_id is null

表结构代码

--建表
--学生表
CREATE TABLE `Student`(
    `s_id` VARCHAR(20),
    `s_name` VARCHAR(20) NOT NULL DEFAULT '',
    `s_birth` VARCHAR(20) NOT NULL DEFAULT '',
    `s_sex` VARCHAR(10) NOT NULL DEFAULT '',
    PRIMARY KEY(`s_id`)
);
--课程表
CREATE TABLE `Course`(
    `c_id`  VARCHAR(20),
    `c_name` VARCHAR(20) NOT NULL DEFAULT '',
    `t_id` VARCHAR(20) NOT NULL,
    PRIMARY KEY(`c_id`)
);

--教师表
CREATE TABLE `Teacher`(
    `t_id` VARCHAR(20),
    `t_name` VARCHAR(20) NOT NULL DEFAULT '',
    PRIMARY KEY(`t_id`)
);

--成绩表
CREATE TABLE `Score`(
    `s_id` VARCHAR(20),
    `c_id`  VARCHAR(20),
    `s_score` INT(3),
    PRIMARY KEY(`s_id`,`c_id`)
);

--插入学生表测试数据
insert into Student values('01' , '赵雷' , '1990-01-01' , '男');
insert into Student values('02' , '钱电' , '1990-12-21' , '男');
insert into Student values('03' , '孙风' , '1990-05-20' , '男');
insert into Student values('04' , '李云' , '1990-08-06' , '男');
insert into Student values('05' , '周梅' , '1991-12-01' , '女');
insert into Student values('06' , '吴兰' , '1992-03-01' , '女');
insert into Student values('07' , '郑竹' , '1989-07-01' , '女');
insert into Student values('08' , '王菊' , '1990-01-20' , '女');

--课程表测试数据
insert into Course values('01' , '语文' , '02');
insert into Course values('02' , '数学' , '01');
insert into Course values('03' , '英语' , '03');

 
--教师表测试数据
insert into Teacher values('01' , '张三');
insert into Teacher values('02' , '李四');
insert into Teacher values('03' , '王五');

 

--成绩表测试数据
insert into Score values('01' , '01' , 80);
insert into Score values('01' , '02' , 90);
insert into Score values('01' , '03' , 99);
insert into Score values('02' , '01' , 70);
insert into Score values('02' , '02' , 60);
insert into Score values('02' , '03' , 80);
insert into Score values('03' , '01' , 80);
insert into Score values('03' , '02' , 80);
insert into Score values('03' , '03' , 80);
insert into Score values('04' , '01' , 50);
insert into Score values('04' , '02' , 30);
insert into Score values('04' , '03' , 20);
insert into Score values('05' , '01' , 76);
insert into Score values('05' , '02' , 87);
insert into Score values('06' , '01' , 31);
insert into Score values('06' , '03' , 34);
insert into Score values('07' , '02' , 89);
insert into Score values('07' , '03' , 98);