MySQL进阶实战查询篇

原创已于 2025-04-15 09:42:30 修改 · 1k 阅读

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#mysql #数据库

于 2025-04-15 09:41:27 首次发布

一，数据表介绍

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

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

--3.教师表
Teacher(TId,Tname)
--TId 教师编号,Tname 教师姓名

--4.成绩表
SC(SId,CId,score)
--SId 学生编号,CId 课程编号,score 分数

学生表 Student

create table Student(SId varchar(10),Sname varchar(10),Sage datetime,Ssex varchar(10));

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' , '1990-12-20' , '男');

insert into Student values('04' , '李云' , '1990-12-06' , '男');

insert into Student values('05' , '周梅' , '1991-12-01' , '女');

insert into Student values('06' , '吴兰' , '1992-01-01' , '女');

insert into Student values('07' , '郑竹' , '1989-01-01' , '女');

insert into Student values('09' , '张三' , '2017-12-20' , '女');

insert into Student values('10' , '李四' , '2017-12-25' , '女');

insert into Student values('11' , '李四' , '2012-06-06' , '女');

insert into Student values('12' , '赵六' , '2013-06-13' , '女');

insert into Student values('13' , '孙七' , '2014-06-01' , '女');

科目表 Course

create table Course(CId varchar(10),Cname nvarchar(10),TId varchar(10));

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 Teacher

create table Teacher(TId varchar(10),Tname varchar(10));

insert into Teacher values('01' , '张三');

insert into Teacher values('02' , '李四');

insert into Teacher values('03' , '王五');

成绩表 SC

create table SC(SId varchar(10),CId varchar(10),score decimal(18,1));

insert into SC values('01' , '01' , 80);

insert into SC values('01' , '02' , 90);

insert into SC values('01' , '03' , 99);

insert into SC values('02' , '01' , 70);

insert into SC values('02' , '02' , 60);

insert into SC values('02' , '03' , 80);

insert into SC values('03' , '01' , 80);

insert into SC values('03' , '02' , 80);

insert into SC values('03' , '03' , 80);

insert into SC values('04' , '01' , 50);

insert into SC values('04' , '02' , 30);

insert into SC values('04' , '03' , 20);

insert into SC values('05' , '01' , 76);

insert into SC values('05' , '02' , 87);

insert into SC values('06' , '01' , 31);

insert into SC values('06' , '03' , 34);

insert into SC values('07' , '02' , 89);

insert into SC values('07' , '03' , 98);

二，题目

1.查询" 01 "课程比" 02 "课程成绩高的学生的信息及课程分数

2.查询同时存在" 01 "课程和" 02 "课程的情况

3.查询存在" 01 "课程但可能不存在" 02 "课程的情况(不存在时显示为 null )

4.查询不存在" 01 "课程但存在" 02 "课程的情况

5.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

6.查询在 SC 表存在成绩的学生信息

7.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(没成绩的显示为 null )

8.查有成绩的学生信息

9.查询「李」姓老师的数量

10.查询学过「张三」老师授课的同学的信息

11.查询没有学全所有课程的同学的信息

12.查询至少有一门课与学号为" 01 "的同学所学相同的同学的信

13.查询和" 01 "号的同学学习的课程完全相同的其他同学的信息

14.查询没学过"张三"老师讲授的任一门课程的学生姓名

15.查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩

16.检索" 01 "课程分数小于 60，按分数降序排列的学生信息

17.按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩

18.查询各科成绩最高分、最低分和平均分：（以如下形式显示：课程 ID，课程 name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90要求输出课程号和选修人数，查询结果按人数降序排列，若人数相同，按课程号升序排列）

19.按各科成绩进行排序，并显示排名， Score 重复时保留名次空缺

20.按各科成绩进行排序，并显示排名， Score 重复时合并名次

21.查询学生的总成绩，并进行排名，总分重复时保留名次空缺

22.查询学生的总成绩，并进行排名，总分重复时不保留名次空缺

23.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

24.查询各科成绩前三名的记录

25.查询每门课程被选修的学生数

26.查询出只选修两门课程的学生学号和姓名

27.查询男生、女生人数

28.查询名字中含有「风」字的学生信息

29.查询同名同性学生名单，并统计同名人数

30.查询 1990 年出生的学生名单

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

32.查询平均成绩大于等于 85 的所有学生的学号、姓名和平均成绩

33.查询课程名称为「数学」，且分数低于 60 的学生姓名和分数

34.查询所有学生的课程及分数情况（存在学生没成绩，没选课的情况）

35.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

36.查询不及格的课程

37.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

38.求每门课程的学生人数

39.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

40.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

41.查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩

42.查询每门功成绩最好的前两名

43.统计每门课程的学生选修人数（超过 5 人的课程才统计）。

44.检索至少选修两门课程的学生学号

45.查询选修了全部课程的学生信息

46.查询各学生的年龄，只按年份来算

47.按照出生日期来算，当前月日 < 出生年月的月日则，年龄减一

48.查询本周过生日的学生

49.查询下周过生日的学生

50.查询本月过生日的学生

51.查询下月过生日的学生

三，解析

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.*,sc.Cid,sc.score from 
(SELECT Sid,max(score) as m  FROM sc where Cid = 01 or Cid = 02 GROUP BY Sid HAVING max(score) > min(score)) as A,sc,student 
where A.m=sc.score and sc.Cid = 01 and A.Sid = student.SId ;

2.查询同时存在" 01 "课程和" 02 "课程的情况

select * from 
(select * from sc where Cid = 01) as A,
(select * from sc where Cid = 02) as B
where A.Sid = B.Sid;

3.查询存在" 01 "课程但可能不存在" 02 "课程的情况(不存在时显示为 null )

select * from 
(select * from sc where Cid = 01) as A LEFT JOIN
(select * from sc where Cid = 02) as B
ON A.Sid = B.Sid;

4.查询不存在" 01 "课程但存在" 02 "课程的情况

select * from 
(select * from sc where Cid = 01) as A RIGHT JOIN
(select * from sc where Cid = 02) as B
ON A.Sid = B.Sid;

5.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 student.*,a.avg from
 (select Sid,AVG(score) as avg from sc GROUP BY Sid HAVING AVG(score) > 60) as a,student where a.Sid=student.SId;

6.查询在 SC 表存在成绩的学生信息

SELECT distinct sc.SId,student.Sname,student.Sage,student.Ssex 
from sc,student 
where sc.SId=student.SId;

7.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(没成绩的显示为 null )

select s.sid, s.sname,r.coursenumber,r.scoresum
from (
    (select student.sid,student.sname 
    from student
    )s 
    left join 
    (select 
        sc.sid, sum(sc.score) as scoresum, count(sc.cid) as coursenumber
        from sc 
        group by sc.sid
    )r 
   on s.sid = r.sid
);

8.查有成绩的学生信息

SELECT s.SId,student.Sname,student.Sage,student.Ssex 
from (select SId from sc GROUP BY SId) as s,student 
where s.Sid = student.Sid ;

9.查询「李」姓老师的数量

SELECT COUNT(*) from teacher where Tname like "李%"

10.查询学过「张三」老师授课的同学的信息

select student.* 
from (select Tid from teacher where Tname = "张三")as t,course,sc,student 
where t.Tid=course.CId AND sc.CId=course.CId AND sc.SId=student.SId;

11.查询没有学全所有课程的同学的信息

select student.* 
from student 
left JOIN (select SId,COUNT(SId)as C from sc GROUP BY SId)as s  
on s.SId=student.SId 
where C < 3 or c is NULL;

12.查询至少有一门课与学号为" 01 "的同学所学相同的同学的信

SELECT DISTINCT sid,sname,sage,ssex  
from (select CId from sc where SId = "01")as a 
LEFT JOIN
(select student.*,cid from sc,student where sc.SId=student.SId and sc.sid != "01")as b 
on a.cid = b.cid;

13.查询和" 01 "号的同学学习的课程完全相同的其他同学的信息

select student.* from 
(select sid from (SELECT cid from sc where sid = "01")as a 
left JOIN(select sid,cid from sc where sc.sid !="01")as b 
on a.CId=b.CId 
GROUP BY sid HAVING COUNT(sid) = 3)as c,student 
where student.SId = c.sid;

14.查询没学过"张三"老师讲授的任一门课程的学生姓名

select * from student
    where student.sid not in(
        select sc.sid from sc where sc.cid in(
            select course.cid from course where course.tid in(
                select teacher.tid from teacher where tname = "张三"
            )
        )
    );

15.查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩

select student.SId, student.Sname,b.avg
from student RIGHT JOIN
(select sid, AVG(score) as avg from sc
    where sid in (
              select sid from sc 
              where score<60 
              GROUP BY sid 
              HAVING count(score)>1)
    GROUP BY sid) b on student.sid=b.sid;

16.检索" 01 "课程分数小于 60，按分数降序排列的学生信息

select student.*, sc.score from student, sc
where student.sid = sc.sid
and sc.score < 60
and cid = "01"
ORDER BY sc.score DESC;

17.按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩

select *  from sc 
left join (
    select sid,avg(score) as avscore from sc 
    group by sid
    )r 
on sc.sid = r.sid
order by avscore desc;

18.查询各科成绩最高分、最低分和平均分：（以如下形式显示：课程 ID，课程 name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90要求输出课程号和选修人数，查询结果按人数降序排列，若人数相同，按课程号升序排列）

select 
sc.CId ,
max(sc.score)as 最高分,
min(sc.score)as 最低分,
AVG(sc.score)as 平均分,
count(*)as 选修人数,
sum(case when sc.score>=60 then 1 else 0 end )/count(*)as 及格率,
sum(case when sc.score>=70 and sc.score<80 then 1 else 0 end )/count(*)as 中等率,
sum(case when sc.score>=80 and sc.score<90 then 1 else 0 end )/count(*)as 优良率,
sum(case when sc.score>=90 then 1 else 0 end )/count(*)as 优秀率 
from sc
GROUP BY sc.CId
ORDER BY count(*)DESC, sc.CId ASC

19.按各科成绩进行排序，并显示排名， Score 重复时保留名次空缺

select a.cid, a.sid, a.score, count(b.score)+1 as rank
from sc as a 
left join sc as b 
on a.score<b.score and a.cid = b.cid
group by a.cid, a.sid,a.score
order by a.cid, rank ASC;

20.按各科成绩进行排序，并显示排名， Score 重复时合并名次

set @crank=0;
select q.sid, total, @crank := @crank +1 as rank from(
select sc.sid, sum(sc.score) as total from sc
group by sc.sid
order by total desc)q;

21.查询学生的总成绩，并进行排名，总分重复时保留名次空缺

select a.cid, a.sid, a.score, count(b.score)+1 as rank
from sc as a 
left join sc as b 
on a.score<b.score and a.cid = b.cid
group by a.cid, a.sid,a.score
order by a.cid, rank ASC;

22.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

select course.cname, course.cid,
sum(case when sc.score<=100 and sc.score>85 then 1 else 0 end) as "[100-85]",
sum(case when sc.score<=85 and sc.score>70 then 1 else 0 end) as "[85-70]",
sum(case when sc.score<=70 and sc.score>60 then 1 else 0 end) as "[70-60]",
sum(case when sc.score<=60 and sc.score>0 then 1 else 0 end) as "[60-0]"
from sc left join course
on sc.cid = course.cid
group by sc.cid;

23.查询各科成绩前三名的记录

select * from sc
where (
select count(*) from sc as a 
where sc.cid = a.cid and sc.score<a.score 
)< 3
order by cid asc, sc.score desc;

24.查询每门课程被选修的学生数

select cid, count(sid) from sc 
group by cid;

25.查询出只选修两门课程的学生学号和姓名

select student.sid, student.sname from student
where student.sid in
(select sc.sid from sc
group by sc.sid
having count(sc.cid)=2
);

26.查询男生、女生人数

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

27.查询名字中含有「风」字的学生信息

select *
from student 
where student.Sname like '%风%'

28.查询同名同性学生名单，并统计同名人数

select sname, count(*) from student
group by sname
having count(*)>1;

29.查询 1990 年出生的学生名单

select *
from student
where YEAR(student.Sage)=1990;

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

select sc.cid, course.cname, AVG(SC.SCORE) as average from sc, course
where sc.cid = course.cid
group by sc.cid 
order by average desc,cid asc;

31.查询平均成绩大于等于 85 的所有学生的学号、姓名和平均成绩

select student.sid, student.sname, AVG(sc.score) as aver from student, sc
where student.sid = sc.sid
group by sc.sid
having aver > 85;

32.查询课程名称为「数学」，且分数低于 60 的学生姓名和分数

select student.sname, sc.score from student, sc, course
where student.sid = sc.sid
and course.cid = sc.cid
and course.cname = "数学"
and sc.score < 60;

33.查询所有学生的课程及分数情况（存在学生没成绩，没选课的情况）

select student.sname, cid, score from student
left join sc
on student.sid = sc.sid;

34.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

select student.sname, course.cname,sc.score from student,course,sc
where sc.score>70
and student.sid = sc.sid
and sc.cid = course.cid;

35.查询不及格的课程

select cid from sc
where score< 60
group by cid;
select DISTINCT sc.CId
from sc
where sc.score <60;

36.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

select student.sid,student.sname 
from student,sc
where cid="01"
and score>=80
and student.sid = sc.sid;

37.求每门课程的学生人数

select sc.CId,count(*) as 学生人数
from sc
GROUP BY sc.CId;

38.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

select student.*, sc.score, sc.cid from student, teacher, course,sc 
where teacher.tid = course.tid
and sc.sid = student.sid
and sc.cid = course.cid
and teacher.tname = "张三"
having max(sc.score);
select student.*, sc.score, sc.cid from student, teacher, course,sc 
where teacher.tid = course.tid
and sc.sid = student.sid
and sc.cid = course.cid
and teacher.tname = "张三"
order by score desc
limit 1;

39.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

select student.*, sc.score, sc.cid from student, teacher, course,sc 
where teacher.tid = course.tid
and sc.sid = student.sid
and sc.cid = course.cid
and teacher.tname = "张三"
and sc.score = (
    select Max(sc.score) 
    from sc,student, teacher, course
    where teacher.tid = course.tid
    and sc.sid = student.sid
    and sc.cid = course.cid
    and teacher.tname = "张三"
);

40.查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩

select  a.cid, a.sid,  a.score from sc as a
inner join 
sc as b
on a.sid = b.sid
and a.cid != b.cid
and a.score = b.score
group by cid, sid;

41.查询每门功成绩最好的前两名

select a.sid,a.cid,a.score from sc as a 
left join sc as b 
on a.cid = b.cid and a.score<b.score
group by a.cid, a.sid
having count(b.cid)<2
order by a.cid;

42.统计每门课程的学生选修人数（超过 5 人的课程才统计）。

select sc.cid, count(sid) as cc from sc
group by cid
having cc >5;

43.检索至少选修两门课程的学生学号

select sid, count(cid) as cc from sc
group by sid
having cc>=2;

44.查询选修了全部课程的学生信息

select student.*
from sc ,student 
where sc.SId=student.SId
GROUP BY sc.SId
HAVING count(*) = (select DISTINCT count(*) from course )

45.查询各学生的年龄，只按年份来算

select student.SId as 学生编号,student.Sname  as  学生姓名,
TIMESTAMPDIFF(YEAR,student.Sage,CURDATE()) as 学生年龄
from student

46.按照出生日期来算，当前月日 < 出生年月的月日，则年龄减一

select student.SId as 学生编号,student.Sname  as  学生姓名,
TIMESTAMPDIFF(YEAR,student.Sage,CURDATE()) as 学生年龄
from student

47.查询本周过生日的学生

select *
from student 
where WEEKOFYEAR(student.Sage)=WEEKOFYEAR(CURDATE());

48.查询下周过生日的学生

select *
from student 
where WEEKOFYEAR(student.Sage)=WEEKOFYEAR(CURDATE())+1;

49.查询本月过生日的学生

select *
from student 
where MONTH(student.Sage)=MONTH(CURDATE());

50.查询下月过生日的学生

select *
from student 
where MONTH(student.Sage)=MONTH(CURDATE())+1;