IT评测·应用市场-qidao123.com

标题: MySQL必学！！！（练习题50道精选） [打印本页]

---

作者: 美食家大橙子    时间: 2024-8-19 05:14
标题: MySQL必学！！！（练习题50道精选）
一、 数据表介绍

数据表介绍
–1.学生表

1. Student(SId,Sname,Sage,Ssex)
2. --SId 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别

复制代码

–2.课程表

1. Course(CId,Cname,TId)
2. --CId 课程编号,Cname 课程名称,TId 教师编号

复制代码

–3.教师表

1. Teacher(TId,Tname)
2. --TId 教师编号,Tname 教师姓名

复制代码

–4.成绩表

1. --SId 学生编号,CId 课程编号,score 分数

复制代码

二、搭建情况

学生表 Student

1. create table Student(SId varchar(10),Sname varchar(10),Sage datetime,Ssex varchar(10));
2. insert into Student values('01' , '赵雷' , '1990-01-01' , '男');
3. insert into Student values('02' , '钱电' , '1990-12-21' , '男');
4. insert into Student values('03' , '孙风' , '1990-12-20' , '男');
5. insert into Student values('04' , '李云' , '1990-12-06' , '男');
6. insert into Student values('05' , '周梅' , '1991-12-01' , '女');
7. insert into Student values('06' , '吴兰' , '1992-01-01' , '女');
8. insert into Student values('07' , '郑竹' , '1989-01-01' , '女');
9. insert into Student values('09' , '张三' , '2017-12-20' , '女');
10. insert into Student values('10' , '李四' , '2017-12-25' , '女');
11. insert into Student values('11' , '李四' , '2012-06-06' , '女');
12. insert into Student values('12' , '赵六' , '2013-06-13' , '女');
13. insert into Student values('13' , '孙七' , '2014-06-01' , '女');

复制代码

科目表 Course

1. create table Course(CId varchar(10),Cname nvarchar(10),TId varchar(10));
2. insert into Course values('01' , '语文' , '02');
3. insert into Course values('02' , '数学' , '01');
4. insert into Course values('03' , '英语' , '03');

复制代码

教师表 Teacher

1. create table Teacher(TId varchar(10),Tname varchar(10));
2. insert into Teacher values('01' , '张三');
3. insert into Teacher values('02' , '李四');
4. insert into Teacher values('03' , '王五');

复制代码

成绩表 SC

1. create table SC(SId varchar(10),CId varchar(10),score decimal(18,1));
2. insert into SC values('01' , '01' , 80);
3. insert into SC values('01' , '02' , 90);
4. insert into SC values('01' , '03' , 99);
5. insert into SC values('02' , '01' , 70);
6. insert into SC values('02' , '02' , 60);
7. insert into SC values('02' , '03' , 80);
8. insert into SC values('03' , '01' , 80);
9. insert into SC values('03' , '02' , 80);
10. insert into SC values('03' , '03' , 80);
11. insert into SC values('04' , '01' , 50);
12. insert into SC values('04' , '02' , 30);
13. insert into SC values('04' , '03' , 20);
14. insert into SC values('05' , '01' , 76);
15. insert into SC values('05' , '02' , 87);
16. insert into SC values('06' , '01' , 31);
17. insert into SC values('06' , '03' , 34);
18. insert into SC values('07' , '02' , 89);
19. insert into SC values('07' , '03' , 98);

复制代码

三、练习题

• 查询" 01 “课程比” 02 "课程成绩高的学生的信息及课程分数
  

1. select * from  (
2.     ->     select t1.SId, class1, class2
3.     ->     from
4.     ->         (SELECT SId, score as class1 FROM SC WHERE SC.CId = '01') AS t1,
5.     ->         (SELECT SId, score as class2 FROM SC WHERE SC.CId = '02') AS t2
6.     ->     where t1.SId = t2.SId and t1.class1 > t2.class2
7.     -> ) r
8.     -> LEFT JOIN Student
9.     -> ON Student.SId = r.SId;

复制代码

1.1 查询同时存在" 01 “课程和” 02 "课程的情况

1. select * from      
2. (select * from SC where SC.CId = '01') as t1,     
3. (select * from SC where SC.CId = '02') as t2
4. where t1.SId = t2.SId;

复制代码

1.2 查询存在" 01 “课程但可能不存在” 02 "课程的情况(不存在时表现为 null )

1. select * from
2.     -> (select * from SC where SC.CId = '01') as t1
3.     -> left join
4.     -> (select * from SC where SC.CId = '02') as t2
5.     -> on t1.SId = t2.SId;

复制代码

1.3 查询不存在" 01 “课程但存在” 02 "课程的情况

1. > select * from SC
2.     -> where SC.SId not in (
3.     ->     select SId from SC
4.     ->     where SC.CId = '01'
5.     -> )
6.     -> AND SC.CId= '02';

复制代码

• 查询平均成绩大于等于 60 分的同砚的学生编号和学生姓名和平均成绩
  

1. > select Student.SId, Student.Sname, r.ss from Student right join(
2.     ->       select SId, AVG(score) AS ss from SC
3.     ->       GROUP BY SId
4.     ->       HAVING AVG(score)> 60
5.     -> )r on Student.SId = r.SId;

复制代码

• 查询在 SC 表存在成绩的学生信息
  

1. > select DISTINCT Student.*
2.     -> from Student,SC
3.     -> where Student.SId=SC.SId
4.     -> ;

复制代码

• 查询全部同砚的学生编号、学生姓名、选课总数、全部课程的总成绩(没成绩的表现为 null )
  

1. > select Student.sid, Student.sname,r.coursenumber,r.scoresum
2.     -> from Student,
3.     -> (select SC.sid, sum(SC.score) as scoresum, count(SC.cid) as coursenumber from SC
4.     -> group by SC.sid)r
5.     -> where Student.sid = r.sid;

复制代码

4.1查有成绩的学生信息

1. > select * from Student
2.     -> where Student.sid in (select SC.sid from SC);

复制代码

• 查询「李」姓老师的数目
  

1. > select count(*)
2.     -> from Teacher
3.     -> where tname like '李%';

复制代码

• 查询学过「张三」老师授课的同砚的信息
  

1. > select Student.* from Student,Teacher,Course,SC
2.     -> where
3.     ->     Student.sid = SC.sid
4.     ->     and Course.cid=SC.cid
5.     ->     and Course.tid =Teacher.tid
6.     ->     and tname = '张三';

复制代码

• 查询没有学全全部课程的同砚的信息
  

1. > select * from Student
2.     -> where Student.sid not in (
3.     ->   select SC.sid from SC
4.     ->   group by SC.sid
5.     ->   having count(SC.cid)= (select count(cid) from Course)
6.     -> );

复制代码

• 查询至少有一门课与学号为" 01 "的同砚所学雷同的同砚的信
  

1. > select * from Student
2.     -> where Student.sid in (
3.     ->     select SC.sid from SC
4.     ->     where SC.cid in(
5.     ->         select SC.cid from SC
6.     ->         where SC.sid = '01'
7.     ->     )
8.     -> );

复制代码

• 查询和" 01 "号的同砚学习的课程 完全雷同的其他同砚的信息
  

1. > SELECT a.SId, a.Sname, a.Sage, a.Ssex
2.     -> FROM Student a, SC b
3.     -> WHERE a.SId = b.SId AND b.CId IN (
4.     ->     SELECT CId
5.     ->     FROM SC
6.     ->     WHERE SId = '01'
7.     -> ) AND a.SId <> '01';

复制代码

• 查询没学过"张三"老师讲授的任一门课程的学生姓名
  

1. > select * from Student
2.     ->      where Student.sid not in(
3.     ->         select SC.sid from SC,Course,Teacher
4.     ->         where
5.     ->             SC.cid = Course.cid
6.     ->              and Course.tid = Teacher.tid
7.     ->             and Teacher.tname= "张三");

复制代码

• 查询两门及其以上不合格课程的同砚的学号，姓名及其平均成绩
  

1. select Student.SId, Student.Sname,b.avg
2.     -> from Student RIGHT JOIN
3.     -> (select sid, AVG(score) as avg from SC
4.     ->     where sid in (
5.     ->               select sid from SC
6.     ->               where score<60
7.     ->               GROUP BY sid
8.     ->               HAVING count(score)>1)
9.     ->     GROUP BY sid) b on Student.sid=b.sid;

复制代码

• 检索" 01 "课程分数小于 60，按分数降序排列的学生信息
  

1. > select Student.*, SC.score from Student, SC
2.     -> where Student.sid = SC.sid
3.     -> and SC.score < 60
4.     -> and cid = "01"
5.     -> ORDER BY SC.score DESC;

复制代码

• 按平均成绩从高到低表现全部学生的全部课程的成绩以及平均成绩
  

1. > select *  from SC
2.     -> left join (
3.     ->     select sid,avg(score) as avscore from SC
4.     ->     group by sid
5.     ->     )r
6.     -> on SC.sid = r.sid
7.     -> order by avscore desc;

复制代码

• 查询各科成绩最高分、最低分和平均分：
  以如下情势表现：课程 ID，课程 name，最高分，最低分，平均分，合格率，中等率，优良率，良好率
  合格为>=60，中等为：70-80，优良为：80-90，良好为：>=90
  要求输出课程号和选修人数，查询结果按人数降序排列，若人数雷同，按课程号升序排列
  
• 按各科成绩举行排序，并表现排名， Score 重复时保存名次空缺
  

1. > select
2.     -> SC.CId ,
3.     -> max(SC.score)as 最高分,
4.     -> min(SC.score)as 最低分,
5.     -> AVG(SC.score)as 平均分,
6.     -> count(*)as 选修人数,
7.     -> sum(case when SC.score>=60 then 1 else 0 end )/count(*)as 及格率,
8.     -> sum(case when SC.score>=70 and SC.score<80 then 1 else 0 end )/count(*)as        中等率,
9.     -> sum(case when SC.score>=80 and SC.score<90 then 1 else 0 end )/count(*)as        优良率,
10.     -> sum(case when SC.score>=90 then 1 else 0 end )/count(*)as 优秀率
11.     -> from SC
12.     -> GROUP BY SC.CId
13.     -> ORDER BY count(*)DESC, SC.CId ASC
14.     -> ;

复制代码

• 查询学生的总成绩，并举行排名，总分重复时保存名次空缺
  

1. [/code] [list=1]
2. [*] 统计各科成绩各分数段人数：课程编号，课程名称，[100-85]，[85-70]，[70-60]，[60-0] 及所占百分比
3. [*] 查询各科成绩前三名的纪录
4. [/list] [code]> select * from SC
5.     -> where (
6.     -> select count(*) from SC as a
7.     -> where SC.cid = a.cid and SC.score<a.score
8.     -> )< 3
9.     -> order by cid asc, SC.score desc;

复制代码

• 查询每门课程被选修的学生数
  

1. > select cid, count(sid) from SC
2.     -> group by cid;

复制代码

• 查询出只选修两门课程的学生学号和姓名
  

1. > select Student.sid, Student.sname from Student
2.     -> where Student.sid in
3.     -> (select SC.sid from SC
4.     -> group by SC.sid
5.     -> having count(SC.cid)=2
6.     -> );

复制代码

• 查询男生、女生人数
  

1. > select ssex, count(*) from Student
2.     -> group by ssex;

复制代码

• 查询名字中含有「风」字的学生信息
  

1. > select *
2.     -> from Student
3.     -> where Student.Sname like '%风%'
4.     -> ;

复制代码

• 查询同名同性学生名单，并统计同名人数
  

1. > select sname, count(*) from Student
2.     -> group by sname
3.     -> having count(*)>1;

复制代码

• 查询 1990 年出生的学生名单
  

1. > select *
2.     -> from Student
3.     -> where YEAR(Student.Sage)=1990;

复制代码

25. 查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩雷同时，按课程编号升序排列

• 查询平均成绩大于等于 85 的全部学生的学号、姓名和平均成绩
  
• 查询课程名称为「数学」，且分数低于 60 的学生姓名和分数
  

1. > select Student.sname, SC.score from Student, SC, Course
2.     -> where Student.sid = SC.sid
3.     -> and Course.cid = SC.cid
4.     -> and Course.cname = "数学"
5.     -> and SC.score < 60;

复制代码

• 查询全部学生的课程及分数情况（存在学生没成绩，没选课的情况）
  

1. select Student.sname, cid, score from Student
2. left join SC
3. on Student.sid = SC.sid;

复制代码

• 查询任何一门课程成绩在 70 分以上的姓名、课程名称和分数
  

1. > select Student.sname, Course.cname,SC.score from Student,Course,SC
2.     -> where SC.score>70
3.     -> and Student.sid = SC.sid
4.     -> and SC.cid = Course.cid;

复制代码

• 查询不合格的课程
  

1. > select DISTINCT SC.CId
2.     -> from SC
3.     -> where SC.score <60;

复制代码

• 查询课程编号为 01 且课程成绩在 80 分以上的学生的学号和姓名
  

1. > select Student.sid,Student.sname
2.     -> from Student,SC
3.     -> where cid="01"
4.     -> and score>=80
5.     -> and Student.sid = SC.sid;

复制代码

• 求每门课程的学生人数
  

1. > select SC.CId,count(*) as 学生人数
2.     -> from SC
3.     -> GROUP BY SC.CId;

复制代码

• 成绩不重复，查询选修「张三」老师所授课程的学生中，成绩最高的学生信息及其成绩
  

1. l> select Student.*, SC.score, SC.cid from Student, Teacher, Course,SC
2.     -> where Teacher.tid = Course.tid
3.     -> and SC.sid = Student.sid
4.     -> and SC.cid = Course.cid
5.     -> and Teacher.tname = "张三"
6.     -> order by score desc
7.     -> limit 1;

复制代码

• 成绩有重复的情况下，查询选修「张三」老师所授课程的学生中，成绩最高的学生信息及其成绩
  

1. > select Student.*, SC.score, SC.cid from Student, Teacher, Course,SC
2.     -> where Teacher.tid = Course.tid
3.     -> and SC.sid = Student.sid
4.     -> and SC.cid = Course.cid
5.     -> and Teacher.tname = "张三"
6.     -> and SC.score = (
7.     ->     select Max(SC.score)
8.     ->     from SC,Student, Teacher, Course
9.     ->     where Teacher.tid = Course.tid
10.     ->     and SC.sid = Student.sid
11.     ->     and SC.cid = Course.cid
12.     ->     and Teacher.tname = "张三"
13.     -> );

复制代码

• 查询差别课程成绩雷同的学生的学生编号、课程编号、学生成绩
  
• 查询每门功成绩最好的前两名
  

1. [/code] [list=1]
2. [*]统计每门课程的学生选修人数（超过 5 人的课程才统计）。
3. [/list] [code]> select SC.cid, count(sid) as cc from SC
4.     -> group by cid
5.     -> having cc >5;

复制代码

• 检索至少选修两门课程的学生学号
  

1. > select sid, count(cid) as cc from SC
2.     -> group by sid
3.     -> having cc>=2;

复制代码

• 查询选修了全部课程的学生信息
  

1. [/code] [list=1]
2. [*]查询各学生的年岁，只按年份来算
3. [/list] [code]SELECT s.SId, s.SName
4. FROM Student s
5. INNER JOIN SC sc ON s.SId = sc.SId
6. WHERE sc.Score > 80 AND sc.CId != '01';

复制代码

• 按照出生日期来算，当前月日 < 出生年月的月日则，年岁减一
  

1. > select Student.SId as 学生编号,Student.Sname  as  学生姓名,
2.     -> TIMESTAMPDIFF(YEAR,Student.Sage,CURDATE()) as 学生年龄
3.     -> from Student
4.     -> ;

复制代码

• 查询本周过生日的学生
  

1. select *
2. from Student
3. where WEEKOFYEAR(Student.Sage)=WEEKOFYEAR(CURDATE());

复制代码

• 查询下周过生日的学生
  

1. select *
2. from Student
3. where WEEKOFYEAR(Student.Sage)=WEEKOFYEAR(CURDATE())+1;

复制代码

• 查询本月过生日的学生
  

1. l> select *
2.     -> from Student
3.     -> where MONTH(Student.Sage)=MONTH(CURDATE());

复制代码

• 查询下月过生日的学生
  

1. > select *
2.     -> from Student
3.     -> where MONTH(Student.Sage)=MONTH(CURDATE())+1;

复制代码

免责声明：如果侵犯了您的权益，请联系站长，我们会及时删除侵权内容，谢谢合作！更多信息从访问主页：qidao123.com:ToB企服之家，中国第一个企服评测及商务社交产业平台。

---

欢迎光临 IT评测·应用市场-qidao123.com (https://dis.qidao123.com/)

Powered by Discuz! X3.4