习题来源于网络，sql语句会有多个，有本身写的也有从网上抄录的，部分有参考。欢迎指正。
表名和字段
–1.学生表sql
Student(s_id,s_name,s_birth,s_sex) --学生编号,学生姓名, 出生年月,学生性别
–2.课程表
Course(c_id,c_name,t_id) – --课程编号, 课程名称, 教师编号
–3.教师表
Teacher(t_id,t_name) --教师编号,教师姓名
–4.成绩表
Score(s_id,c_id,s_score) --学生编号,课程编号,分数网络
测试数据
--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');学习
--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');测试
--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);spa
练习题和sql语句
-- 一、查询"01"课程比"02"课程成绩高的学生的信息及课程分数数学
select a.* ,b.s_score as 01_score from
student a
join score b on a.s_id=b.s_id and b.c_id='01'
left join score c on a.s_id=c.s_id and c.c_id='02' or c.c_id = NULL where b.s_score>c.s_score;io
-- 二、查询"01"课程比"02"课程成绩低的学生的信息及课程分数
select a.* ,s1.s_score,s2.s_score from Student AS a, Score AS s1, Score AS s2 where a.s_id=s1.s_id And a.s_id = s2.s_id And s1.c_id='01' And s2.c_id='02'
and s1.s_score<s2.s_score;class
-- 三、查询平均成绩大于等于60分的同窗的学生编号和学生姓名和平均成绩
select b.s_id,b.s_name,ROUND(AVG(a.s_score),2) as avg_score from student b join score a on b.s_id = a.s_id GROUP BY b.s_id,b.s_name HAVING avg_score >=60;select
-- 四、查询平均成绩小于60分的同窗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)sql语句
select b.s_id,b.s_name,ROUND(AVG(a.s_score),2) as avg_score from
student b
left join score a on b.s_id = a.s_id
GROUP BY b.s_id HAVING avg_score <60
union
select a.s_id,a.s_name,0 as avg_score from
student a
where a.s_id not in (
select distinct s_id from score);
select a.s_id,a.s_name, Round(avg(IFNULL(s.s_score,0)),2) avg_score from Student a left join Score s on a.s_id=s.s_id group by a.s_id having avg_score<60;
-- 五、查询全部同窗的学生编号、学生姓名、选课总数、全部课程的总成绩
select a.s_id,a.s_name,count(s.c_id),IFNULL(sum(s.s_score),0) from Student a left join Score s on s.s_id=a.s_id group by a.s_id;
select a.s_id,a.s_name,count(b.c_id) as sum_course,sum(b.s_score) as sum_score from
student a
left join score b on a.s_id=b.s_id
GROUP BY a.s_id,a.s_name;
-- 六、查询"李"姓老师的数量
select count(t.t_id) from Teacher t where t.t_name like'李%';
-- 七、查询学过"张三"老师授课的同窗的信息
select a.* from Student a left join Score s on a.s_id= s.s_id left join Course c on c.c_id =s.c_id left join Teacher t on t.t_id=c.t_id where t.t_name ='张三';
select s.* from student s join score e on s.s_id = e.s_id join course c on e.c_id = c.c_id where (select t_id from teacher where t_name = '张三') = c.t_id;
-- 八、查询没学过"张三"老师授课的同窗的信息
select stu.* from Student stu where stu.s_id NOT in(select s.s_id from student s join score e on s.s_id = e.s_id join course c on e.c_id = c.c_id where (select t_id from teacher where t_name = '张三') = c.t_id);
SELECT a.* from student as a where a.s_id not in ( select b.s_id from score as b where b.c_id=( select c.c_id from course as c where c.t_id=( select d.t_id from teacher as d where d.t_name='张三')) );
-- 九、查询学过编号为"01"而且也学过编号为"02"的课程的同窗的信息
select a.* from Student a left join Score s on a.s_id =s.s_id where s.c_id='01' And s.s_id in(select s2.s_id from Score s2 where s2.c_id='02');
select a.* from
student a,score b,score c
where a.s_id = b.s_id and a.s_id = c.s_id and b.c_id='01' and c.c_id='02';
-- 十、查询学过编号为"01"可是没有学过编号为"02"的课程的同窗的信息
select a.* from Student a join Score s1 on s1.s_id =a.s_id where s1.c_id ='01' And s1.s_id NOT in (select s2.s_id from Score s2 where s2.c_id='02');
select a.* from
student a
where a.s_id in (select s_id from score where c_id='01' ) and a.s_id not in(select s_id from score where c_id='02');
-- 十一、查询没有学全全部课程的同窗的信息
select a.* from Student a left join Score s on a.s_id =s.s_id group by a.s_id having count(s.c_id) < (select distinct count(Course.c_id) from Course );
select a.* from Student a where a.s_id NOT in (select s.s_id from Score s group by s.s_id having count(s.c_id)=3);
-- 十二、查询至少有一门课与学号为"01"的同窗所学相同的同窗的信息
select a.* from Student a left join Score s on s.s_id =a.s_id where s.c_id in (select s2.c_id from Score s2 where s2.s_id ='01' ) group by a.s_id;
select * from student where s_id in(
select distinct a.s_id from score a where a.c_id in(select a.c_id from score a where a.s_id='01')
);
-- 1三、查询和"01"号的同窗学习的课程彻底相同的其余同窗的信息
SELECT
Student.*
FROM
Student
WHERE
s_id IN (select s_id from score GROUP BY s_id HAVING GROUP_CONCAT(c_id) = (
SELECT GROUP_CONCAT(c_id) FROM Score WHERE s_id = '02')
);
-- 1四、查询没学过"张三"老师讲授的任一门课程的学生姓名
select a.s_name from student a where a.s_id not in (
select s_id from score where c_id =
(select c_id from course where t_id =(
select t_id from teacher where t_name = '张三')));
select a.s_name from Student a where a.s_id in (select s_id from Score where c_id NOT in
(select c.c_id from Course c left join Teacher t on t.t_id = c.t_id where t.t_name='张三') group by s_id );
-- 1五、查询两门及其以上不及格课程的同窗的学号，姓名及其平均成绩
select a.s_id ,a.s_name,ROUND(avg(s.s_score),2) from Student a left join Score s on s.s_id =a.s_id group by a.s_id having a.s_id in (select s.s_id
from Score s where s.s_score <60 group by s. s_id having count(s.s_id)>=2);
select a.s_id,a.s_name,ROUND(AVG(b.s_score)) from
student a
left join score b on a.s_id = b.s_id
where a.s_id in(
select s_id from score where s_score<60 GROUP BY s_id having count(1)>=2)
GROUP BY a.s_id,a.s_name;
-- 1六、检索"01"课程分数小于60，按分数降序排列的学生信息
select a.*,s.c_id,s.s_score from Student a left join Score s on s.s_id =a.s_id where s.s_score <60 and s.c_id = '01' order by s.s_score desc;
-- 1七、按平均成绩从高到低显示全部学生的全部课程的成绩以及平均成绩
select a.s_id,(select s_score from score where s_id=a.s_id and c_id='01') as 语文,(select s_score from score where s_id=a.s_id and c_id='02') as 数学,(select s_score from score where s_id=a.s_id and c_id='03') as 英语,round(avg(s_score),2) as 平均分 from score a GROUP BY a.s_id ORDER BY 平均分 DESC;