网上关于这套练习题较多使用的是比较老的mysql版本,我使用的是 Server version: 8.0.15 MySQL
练习数据
数据表 --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
创建测试数据
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' , '1990-05-20' , '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('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' , '2017-12-30' , '女');
insert into Student values('12' , '赵六' , '2017-01-01' , '女');
insert into Student values('13' , '孙七' , '2018-01-01' , '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);
练习题目
- 查询" 01 "课程比" 02 "课程成绩高的学生的信息及课程分数 1.1 查询同时存在" 01 "课程和" 02 "课程的情况 1.2 查询存在" 01 "课程但可能不存在" 02 "课程的情况(不存在时显示为 null ) 1.3 查询不存在" 01 "课程但存在" 02 "课程的情况
- 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
- 查询在 SC 表存在成绩的学生信息
- 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 ) 4.1 查有成绩的学生信息
- 查询「李」姓老师的数量
- 查询学过「张三」老师授课的同学的信息
- 查询没有学全所有课程的同学的信息
- 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息
- 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
- 查询没学过"张三"老师讲授的任一门课程的学生姓名
- 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
- 检索" 01 "课程分数小于 60,按分数降序排列的学生信息
- 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
- 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
- 按各科成绩进行排序,并显示排名, Score 重复时保留名次空缺 15.1 按各科成绩进行排序,并显示排名, Score 重复时合并名次
- 查询学生的总成绩,并进行排名,总分重复时保留名次空缺 16.1 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
- 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
- 查询各科成绩前三名的记录
- 查询每门课程被选修的学生数
- 查询出只选修两门课程的学生学号和姓名
- 查询男生、女生人数
- 查询名字中含有「风」字的学生信息
- 查询同名同性学生名单,并统计同名人数
- 查询 1990 年出生的学生名单
- 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
- 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
- 查询课程名称为「数学」,且分数低于 60 的学生姓名和分数
- 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)
- 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
- 查询不及格的课程
- 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
- 求每门课程的学生人数
- 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
- 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
- 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
- 查询每门功成绩最好的前两名
- 统计每门课程的学生选修人数(超过 5 人的课程才统计)。
- 检索至少选修两门课程的学生学号
- 查询选修了全部课程的学生信息
- 查询各学生的年龄,只按年份来算
- 按照出生日期来算,当前月日 < 出生年月的月日则,年龄减一
- 查询本周过生日的学生
- 查询下周过生日的学生
- 查询本月过生日的学生
- 查询下月过生日的学生
参考答案
--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 * from
(select SC.SId, SC.score from SC where SC.CId = '01') as t1 inner join
(select SC.SId, SC.score from SC where SC.CId = '02') as t2 on t1.SId = t2.SId
where t1.score > t2.score
--1.1 查询同时存在" 01 "课程和" 02 "课程的情况
select * from
(select SC.SId, SC.score from SC where SC.CId = '01') as t1 inner join
(select SC.SId, SC.score from SC where SC.CId = '02') as t2 on t1.SId = t2.SId
--1.2 查询存在" 01 "课程但可能不存在" 02 "课程的情况(不存在时显示为 null )
select * from
(select SC.SId, SC.score from SC where SC.CId = '01') as t1 left join
(select SC.SId, SC.score from SC where SC.CId = '02') as t2 on t1.SId = t2.SId
-- 1.3 查询不存在" 01 "课程但存在" 02 "课程的情况
select *
from sc
where SId not in (select SId from sc where CId = '01')
and CId = '02'
-- 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.sid, t1.sname, t2.avgscore
from student as t1 inner join (
select sc.sid, avg(sc.score) as avgscore from sc group by sc.sid
having avgscore >= 60) as t2
on t1.sid = t2.sid
-- 3. 查询在 SC 表存在成绩的学生信息 注意⚠️DISTINCT⚠️关键字
select DISTINCT student.*
from student, sc
where student.sid = sc.sid
-- 4. 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 student.sid, student.sname, t1.coursecount, t1.sumscore
from student inner join (
select sc.sid, count(sc.cid) as coursecount, sum(sc.score) as sumscore from sc group by sc.sid) as t1
on student.sid = t1.sid
-- 4.1 查有成绩的学生信息 注意⚠️EXISTS⚠️关键字
select student.*
from student
where student.sid in (
select DISTINCT sc.sid from sc)
select *
from student
where EXISTS(select * from sc where student.SId=sc.SId)
-- 5. 查询「李」姓老师的数量
select count(*)
from teacher
where teacher.Tname like '李%'
-- 6. 查询学过「张三」老师授课的同学的信息
select student.*
from student, sc
where student.sid = sc.sid
and sc.cid in (select cid from course, teacher where course.tid = teacher.tid and Tname = '张三')
-- 同时连接多张表
select student.*
from teacher ,course ,student, sc
where teacher.Tname='张三'
and teacher.TId=course.TId
and course.CId=sc.CId
and sc.SId=student.SId
-- 7. 查询没有学全所有课程的同学的信息
-- 这种解法不包括什么课都没选的学生
select student.* from student, (select sid, count(cid) as coursecount from sc group by sid) as t1
where student.sid = t1.sid
and t1.coursecount<>3
select student.*
from sc ,student
where sc.SId=student.SId
GROUP BY sc.SId
Having count(*)<(select count(*) from course)
-- 利用笛卡尔积可以把什么课都没选的同学查询出来
select DISTINCT student.*
from
(select student.SId,course.CId
from student,course ) as t1 LEFT JOIN (SELECT sc.SId,sc.CId from sc)as t2 on t1.SId=t2.SId and t1.CId=t2.CId,student
where t2.SId is null
and t1.SId=student.SId
select student.* from student
where student.sid not in (
select student.sid from sc, student
where sc.sid = student.sid
group by sid
having count(*) = (select count(*) from course))
-- 8. 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息
select DISTINCT student.*
from sc, student
where sc.CId in (
select CId from sc where SId='01')
and sc.SId = student.SId
-- 9. 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 DISTINCT student.*
from (
select student.SId, t.CId
from student ,(select sc.CId from sc where sc.SId='01') as t)
as t1 LEFT JOIN sc on t1.SId=sc.SId and t1.CId=sc.CId,student
where sc.SId is not null
and t1.SId=student.SId
and t1.SId <>'01'
-- 10. 查询没学过"张三"老师讲授的任一门课程的学生姓名
-- solution1
select *
from student
where student.SId not in (
select student.SId from (
select student.SId, t.CId from (
select course.CId from course, teacher
where course.TId = teacher.TId and teacher.Tname = '张三') as t, student) as t1
right join sc on t1.SId=sc.SId and t1.CId=sc.CId, student
where t1.SId=student.SId)
-- solution2
select *
from student
where student.SId not in
(
select student.SId
from student left join sc on student.SId=sc.SId
where EXISTS
(select *
from teacher ,course
where teacher.Tname='张三'
and teacher.TId=course.TId
and course.CId=sc.CId))
-- 11.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, t2.avgscore
from student, (select sc.SId, avg(sc.score) as avgscore from sc group by sc.SId) as t2
where student.SId = t2.SId
and student.SId in (
select t1.SId from
(select * from sc
where sc.score < 60) as t1
group by t1.SId
having count(*) >= 2)
-- 12. 检索" 01 "课程分数小于60,按分数降序排列的学生信息
select student.*, t1.score from student, (
select * from sc
where sc.CId = '01' and sc.score < 60) as t1
where student.SId = t1.SId
order by t1.score DESC
-- 13. 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 sc.*, t1.avgscore from sc left join
(select sc.SId, avg(sc.score) as avgscore
from sc group by sc.SId) as t1
on sc.SId = t1.SId
order by t1.avgscore DESC
-- 14. 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
-- 15. 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 *, RANK() OVER(PARTITION BY sc.cid ORDER BY sc.score DESC)排名
FROM sc;
-- 15.1 按各科成绩进行排序,并显示排名, Score 重复时合并名次
SELECT *, DENSE_RANK() OVER(PARTITION BY sc.cid ORDER BY sc.score DESC)排名
FROM sc;
-- 16. 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 sc.SId, RANK() OVER(ORDER BY sum(sc.score) DESC)排名, sum(sc.score) as sumscore
FROM sc
GROUP BY sc.SId
ORDER BY sumscore DESC;
-- 16.1 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
SELECT sc.SId, DENSE_RANK() OVER(ORDER BY sum(sc.score) DESC)排名, sum(sc.score) as sumscore
FROM sc
GROUP BY sc.SId
ORDER BY sumscore DESC;
-- 17. 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 sc.CId, sum(case when sc.score >=85 then 1 else 0 end) as num_100_85,
sum(case when sc.score >=70 and sc.score <85 then 1 else 0 end) as num_85_70,
sum(case when sc.score >= 60 and sc.score < 70 then 1 else 0 end) as num_70_60,
sum(case when sc.score < 60 then 1 else 0 end) as num_60_0,
sum(case when sc.score >=85 then 1 else 0 end)/count(*) as p_100_85,
sum(case when sc.score >=70 and sc.score <85 then 1 else 0 end) /count(*) as p_85_70,
sum(case when sc.score >= 60 and sc.score < 70 then 1 else 0 end)/count(*) as p_70_60,
sum(case when sc.score < 60 then 1 else 0 end)/count(*) as p_60_0
from sc
group by sc.CId
-- 18. 查询各科成绩前三名的记录
SELECT *
FROM(
SELECT *, RANK() OVER (PARTITION BY sc.CId ORDER BY sc.score) as r
FROM sc) as A
WHERE A.r <= 3
-- 19. 查询每门课程被选修的学生数
SELECT sc.CId, COUNT(*)
FROM sc
GROUP BY(sc.CId)
-- 20. 查询出只选修两门课程的学生学号和姓名
SELECT DISTINCT student.SId, student.Sname
FROM student, (
SELECT sc.SId, COUNT(*) as a
FROM sc
GROUP BY(sc.SId)) as A
WHERE student.SId = A.SId
AND A.a = 2
SELECT Distinct student.Sid, student.Sname
FROM student
where student.SId in (
SELECT sc.SId
FROM sc
GROUP BY sc.SId
having count(*)=2)
-- 21. 查询男生、女生人数
SELECT Ssex, count(*)
FROM student
GROUP BY student.Ssex
-- 22. 查询名字中含有「风」字的学生信息
SELECT *
FROM student
WHERE student.sname LIKE '%风%';
-- 23. 查询同名同姓学生名单,并统计同名人数
SELECT Sname, count(*)
FROM student
GROUP BY Sname
HAVING COUNT(*) >1;
-- 24. 查询 1990 年出生的学生名单
SELECT *
FROM student
WHERE sage LIKE '1990-%';
-- 25.查询每门课程的平均成绩,结果按平均成绩降序排列,平均成绩相同时,按课程编号升序排列
SELECT sc.CId, avg(sc.score) as avgscore
FROM sc
GROUP BY sc.CId
ORDER BY avg(sc.score) DESC, sc.CId
-- 26.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, t.avgscore
FROM student, (
SELECT sc.SId, avg(sc.score) as avgscore
FROM sc
GROUP BY sc.SId) as t
WHERE student.SId = t.SId
AND t.avgscore >= 85
-- 27.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, t.score
FROM student, (
SELECT sc.SId, sc.score
FROM sc
WHERE sc.score < 60
AND sc.CId = (SELECT CId FROM course WHERE course.Cname='数学')) as t
WHERE student.SId = t.SId
-- 28.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 st.*, sc.CId, sc.score
FROM student AS st
LEFT JOIN sc
ON st.SId = sc.SId
ORDER BY st.SId, sc.CId;
-- 29.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 student.SId = sc.SId
AND course.CId = sc.CId
AND sc.score > 70
ORDER BY sc.CId
-- 30.查询不及格的课程
SELECT sc.CId, sc.score
FROM sc
WHERE sc.score <60
ORDER BY sc.CId;
-- 31.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 student.SId = sc.SId
AND sc.CId = '01'
AND sc.score > 80
-- 32.求每门课程的学生人数
SELECT sc.CId, count(sc.SId)
FROM sc
GROUP BY sc.CId
-- 33.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, sc
WHERE sc.CId = (SELECT course.CId
FROM course, teacher
WHERE course.TId = teacher.TId
AND teacher.Tname = '张三')
AND student.SId = sc.SId
ORDER BY sc.score DESC
LIMIT 1
-- 34.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 * FROM(
SELECT student.*, sc.score, sc.CId, DENSE_RANK() OVER (ORDER BY sc.score DESC)排名
FROM student, sc
WHERE sc.CId = (SELECT course.CId
FROM course, teacher
WHERE course.TId = teacher.TId
AND teacher.Tname = '张三')
AND student.SId = sc.SId) as t
WHERE t.排名='1'
-- 35.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 sc.SId, sc.CId, sc.score
FROM sc
WHERE sc.score in (
SELECT score FROM(
SELECT sc.score, count(sc.score) as count_people
FROM sc
GROUP BY sc.score) A
WHERE A.count_people > 1)
SELECT s,c,score
FROM
(
SELECT max(score),avg(score),COUNT(score),student.s,c,score
FROM student
LEFT JOIN sc
ON student.s=sc.s
GROUP BY student.s
HAVING max(score)=avg(score) AND COUNT(score)>=2
) A;
-- 36.查询每门功成绩最好的前两名
SELECT *
FROM (SELECT sc.SId, sc.CId, sc.score, row_number() over (PARTITION BY sc.CId ORDER BY sc.score DESC)排名
FROM sc
ORDER BY sc.score DESC) A
WHERE 排名 <= 2
ORDER BY A.CId, A.排名
-- 37.统计每门课程的学生选修人数(超过 5 人的课程才统计)
SELECT *
FROM (
SELECT sc.CId, count(sc.SId) as count_people
FROM sc
GROUP BY sc.CId) A
WHERE A.count_people > 5
SELECT sc.CId,COUNT(sc.CId)
FROM sc
GROUP BY sc.CId
HAVING COUNT(sc.CId)>5 ;
-- 38.检索至少选修两门课程的学生学号
SELECT sc.SId, COUNT(sc.SId)
FROM sc
GROUP BY sc.SId
HAVING COUNT(sc.SId) >= 2
-- 39.查询各学生的年龄,只按年份来算
SELECT SId, Sname, (year(curdate())-year(Sage)) as age
FROM student
ORDER BY age
-- 40.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 SId, Sname,timestampdiff(year,Sage,curdate())年龄
FROM student
ORDER BY 年龄;
-- 41. 查询本周过生日的学生
SET @day =8-dayofweek(curdate());
SELECT *
FROM student
WHERE date_format(Sage, '%m%d')
BETWEEN date_format(curdate(),'%m%d')
AND date_format (date_add(curdate(),interval @day day), '%m%d');
-- 42.查询下周过生日的学生
set @day =9-dayofweek(curdate());
SELECT *
FROM student
WHERE date_format(sage, '%m%d')
BETWEEN date_format (date_add(curdate(),interval @day day), '%m%d')
AND date_format (date_add(curdate(),interval @day+6 day), '%m%d');
-- 43.查询本月过生日的学生
SELECT *
FROM student
WHERE date_format(Sage,'%m')=date_format(curdate(),'%m');
-- 44.查询下月过生日的学生
SELECT *
FROM student
WHERE date_format(Sage,'%m')=date_format(date_add(curdate(),interval 1 month),'%m');