SQL经典练习题(老师、学生、成绩)

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2020-7-5

SQL经典练习题(mysql版)

 

原文链接:
经典SQl练习题(mysql版)

 
  本人自己做了一遍,感觉受益颇多,所以拿出来给大家分享下。其中,由于本人对sql函数部分掌握的不好,15~19题没做出来,是参考的原文。如果有错误或者有更好的sql语句,可以在下方直接评论。
 

创建数据表

学生表Student:

create table Student(Sid varchar(6), 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('08' , '王菊' , '1990-01-20' , '女');

 
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);

 
课程表Course:

create table Course(Cid varchar(10),Cname varchar(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');

 
老师表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')

 
表之间的关系为:

 
 

练习

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.*,a.score from student,(select * from sc where cid=01) as a, (select * from sc where cid=02) as b where student.sid=a.sid and student.sid=b.sid and a.score>b.score;
+------+--------+---------------------+------+-------+
| Sid  | Sname  | Sage                | Ssex | score |
+------+--------+---------------------+------+-------+
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |  70.0 |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |  50.0 |
+------+--------+---------------------+------+-------+
2 rows in set (0.00 sec)

 

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 student.sid,sname,avg(a.score) as avg from student,(select * from sc) as a where student.sid=a.sid group by student.sid having avg>=60;
+------+--------+----------+
| sid  | sname  | avg      |
+------+--------+----------+
| 01   | 赵雷   | 89.66667 |
| 02   | 钱电   | 70.00000 |
| 03   | 孙风   | 80.00000 |
| 05   | 周梅   | 81.50000 |
| 07   | 郑竹   | 93.50000 |
+------+--------+----------+
5 rows in set (0.00 sec)

 

3.查询在 SC 表存在成绩的学生信息

select * from student where sid in (select sid from sc where score is not null);
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 01   | 赵雷   | 1990-01-01 00:00:00 | 男   |
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |
| 05   | 周梅   | 1991-12-01 00:00:00 | 女   |
| 06   | 吴兰   | 1992-03-01 00:00:00 | 女   |
| 07   | 郑竹   | 1989-07-01 00:00:00 | 女   |
+------+--------+---------------------+------+
7 rows in set (0.00 sec)

 

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,count(sc.sid) as count,sum(sc.score) as sum from student left join sc on student.sid=sc.sid group by student.sid;
+------+--------+-------+-------+
| sid  | sname  | count | sum   |
+------+--------+-------+-------+
| 01   | 赵雷   |     3 | 269.0 |
| 02   | 钱电   |     3 | 210.0 |
| 03   | 孙风   |     3 | 240.0 |
| 04   | 李云   |     3 | 100.0 |
| 05   | 周梅   |     2 | 163.0 |
| 06   | 吴兰   |     2 |  65.0 |
| 07   | 郑竹   |     2 | 187.0 |
| 08   | 王菊   |     0 |  NULL |
+------+--------+-------+-------+
8 rows in set (0.00 sec)

 

5.查有成绩的学生信息

select student.* from student,(select * from sc group by sid) as a where student.sid=a.sid;
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 01   | 赵雷   | 1990-01-01 00:00:00 | 男   |
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |
| 05   | 周梅   | 1991-12-01 00:00:00 | 女   |
| 06   | 吴兰   | 1992-03-01 00:00:00 | 女   |
| 07   | 郑竹   | 1989-07-01 00:00:00 | 女   |
+------+--------+---------------------+------+
7 rows in set (0.00 sec)

 

6.查询「李」姓老师的数量

select count(*) from teacher where tname like '李%';
+----------+
| count(*) |
+----------+
|        1 |
+----------+
1 row in set (0.00 sec)

 

7.查询学过「张三」老师授课的同学的信息

select student.* from student,(select sid from sc,course,teacher where sc.cid=course.cid and course.tid=teacher.tid and teacher.tname='张三') as b where student.sid=b.sid;
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 01   | 赵雷   | 1990-01-01 00:00:00 | 男   |
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |
| 05   | 周梅   | 1991-12-01 00:00:00 | 女   |
| 07   | 郑竹   | 1989-07-01 00:00:00 | 女   |
+------+--------+---------------------+------+
6 rows in set (0.00 sec)

 

8.查询没有学全所有课程的同学的信息

select * from student where sid in (select sid from sc group by sid having count(cid) < 3);
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 05   | 周梅   | 1991-12-01 00:00:00 | 女   |
| 06   | 吴兰   | 1992-03-01 00:00:00 | 女   |
| 07   | 郑竹   | 1989-07-01 00:00:00 | 女   |
+------+--------+---------------------+------+
3 rows in set (0.00 sec)

 

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 student.* from student,(select b.sid from (select sid,group_concat(cid) as g from sc group by sid) as a,(select sid,group_concat(cid) as g from sc group by sid) as b where a.sid=01 and a.g=b.g and b.sid!=01) as c where student.sid=c.sid;
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |
+------+--------+---------------------+------+
3 rows in set (0.00 sec)

 

10.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 * from Student where Sid in (select distinct Sid from SC where Cid in (select Cid from SC where Sid='01'));
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 01   | 赵雷   | 1990-01-01 00:00:00 | 男   |
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |
| 05   | 周梅   | 1991-12-01 00:00:00 | 女   |
| 06   | 吴兰   | 1992-03-01 00:00:00 | 女   |
| 07   | 郑竹   | 1989-07-01 00:00:00 | 女   |
+------+--------+---------------------+------+
7 rows in set (0.00 sec)

 

11.查询没学过”张三”老师讲授的任一门课程的学生姓名

select sname from student where sname not in (select s.sname from student as s, course as c, teacher as t, sc where s.sid = sc.sid and sc.cid = c.cid and c.tid = t.tid and t.tname = '张三');
+--------+
| sname  |
+--------+
| 吴兰   |
| 王菊   |
+--------+
2 rows in set (0.01 sec)

 

12.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,avg(sc.score) from student,sc,(select sid from sc where score<60 group by sid having count(score)>=2) as a where student.sid=sc.sid and student.sid=a.sid group by sid;
+------+--------+---------------+
| sid  | sname  | avg(sc.score) |
+------+--------+---------------+
| 04   | 李云   |      33.33333 |
| 06   | 吴兰   |      32.50000 |
+------+--------+---------------+
2 rows in set (0.00 sec)

 

13.检索” 01 “课程分数小于 60,按分数降序排列的学生信息

select student.* from sc,student where sc.sid=student.sid and cid=01 and score<60 order by sc.score desc;
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |
| 06   | 吴兰   | 1992-03-01 00:00:00 | 女   |
+------+--------+---------------------+------+
2 rows in set (0.00 sec)

 

14.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.sid,score_01.score as score_01,score_02.score as score_02,score_03.score as score_03,avg(sc.score) as avg_score from sc left join (select * from sc where cid=01) as score_01 on score_01.sid=sc.sid left join (select * from sc where cid=02) as score_02 on score_02.sid=sc.sid left join (select * from sc where cid=03) as score_03 on score_03.sid=sc.sid group by sid order by avg_score desc;
+------+----------+----------+----------+-----------+
| sid  | score_01 | score_02 | score_03 | avg_score |
+------+----------+----------+----------+-----------+
| 07   |     NULL |     89.0 |     98.0 |  93.50000 |
| 01   |     80.0 |     90.0 |     99.0 |  89.66667 |
| 05   |     76.0 |     87.0 |     NULL |  81.50000 |
| 03   |     80.0 |     80.0 |     80.0 |  80.00000 |
| 02   |     70.0 |     60.0 |     80.0 |  70.00000 |
| 04   |     50.0 |     30.0 |     20.0 |  33.33333 |
| 06   |     31.0 |     NULL |     34.0 |  32.50000 |
+------+----------+----------+----------+-----------+
7 rows in set (0.00 sec)

 

15.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。(方便显示我改了字段名)

select c.cid as cid, c.cname as cname, count(*) as count,
    max(score) as max, min(score) as min, avg(score) as avg,
    sum(case when score >= 60 then 1 else 0 end)/count(*) as pass,
    sum(case when score >= 70 and score < 80 then 1 else 0 end)/count(*) as medium,
    sum(case when score >= 80 and score < 90 then 1 else 0 end)/count(*) as good,
    sum(case when score >= 90 then 1 else 0 end)/count(*) as excellent
from sc, course c
where c.cid = sc.cid
group by c.cid
order by count(*) desc, c.cid asc;
+------+--------+-------+------+------+----------+--------+--------+--------+-----------+
| cid  | cname  | count | max  | min  | avg      | pass   | medium | good   | excellent |
+------+--------+-------+------+------+----------+--------+--------+--------+-----------+
| 01   | 语文   |     6 | 80.0 | 31.0 | 64.50000 | 0.6667 | 0.3333 | 0.3333 |    0.0000 |
| 02   | 数学   |     6 | 90.0 | 30.0 | 72.66667 | 0.8333 | 0.0000 | 0.5000 |    0.1667 |
| 03   | 英语   |     6 | 99.0 | 20.0 | 68.50000 | 0.6667 | 0.0000 | 0.3333 |    0.3333 |
+------+--------+-------+------+------+----------+--------+--------+--------+-----------+
3 rows in set (0.00 sec)

 

16.按平均成绩进行排序,显示总排名和各科排名,Score 重复时保留名次空缺

select s.*, rank_01, rank_02, rank_03, rank_total
from student s
left join (select sid, rank() over(partition by cid order by score desc) as rank_01 from sc where cid=01) A on s.sid=A.sid
left join (select sid, rank() over(partition by cid order by score desc) as rank_02 from sc where cid=02) B on s.sid=B.sid
left join (select sid, rank() over(partition by cid order by score desc) as rank_03 from sc where cid=03) C on s.sid=C.sid
left join (select sid, rank() over(order by avg(score) desc) as rank_total from sc group by sid) D on s.sid=D.sid
order by rank_total asc;
+------+--------+---------------------+------+---------+---------+---------+------------+
| Sid  | Sname  | Sage                | Ssex | rank_01 | rank_02 | rank_03 | rank_total |
+------+--------+---------------------+------+---------+---------+---------+------------+
| 08   | 王菊   | 1990-01-20 00:00:00 | 男   |    NULL |    NULL |    NULL |       NULL |
| 07   | 郑竹   | 1989-07-01 00:00:00 | 女   |    NULL |       2 |       2 |          1 |
| 01   | 赵雷   | 1990-01-01 00:00:00 | 男   |       1 |       1 |       1 |          2 |
| 05   | 周梅   | 1991-12-01 00:00:00 | 女   |       3 |       3 |    NULL |          3 |
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |       1 |       4 |       3 |          4 |
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |       4 |       5 |       3 |          5 |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |       5 |       6 |       6 |          6 |
| 06   | 吴兰   | 1992-03-01 00:00:00 | 女   |       6 |    NULL |       5 |          7 |
+------+--------+---------------------+------+---------+---------+---------+------------+
8 rows in set (0.02 sec)

 

17.按平均成绩进行排序,显示总排名和各科排名,Score 重复时合并名次

select s.*, rank_01, rank_02, rank_03, rank_total
from student s
left join (select sid, dense_rank() over(partition by cid order by score desc) as rank_01 from sc where cid=01) A on s.sid=A.sid
left join (select sid, dense_rank() over(partition by cid order by score desc) as rank_02 from sc where cid=02) B on s.sid=B.sid
left join (select sid, dense_rank() over(partition by cid order by score desc) as rank_03 from sc where cid=03) C on s.sid=C.sid
left join (select sid, dense_rank() over(order by avg(score) desc) as rank_total from sc group by sid) D on s.sid=D.sid
order by rank_total asc;
+------+--------+---------------------+------+---------+---------+---------+------------+
| Sid  | Sname  | Sage                | Ssex | rank_01 | rank_02 | rank_03 | rank_total |
+------+--------+---------------------+------+---------+---------+---------+------------+
| 08   | 王菊   | 1990-01-20 00:00:00 | 男   |    NULL |    NULL |    NULL |       NULL |
| 07   | 郑竹   | 1989-07-01 00:00:00 | 女   |    NULL |       2 |       2 |          1 |
| 01   | 赵雷   | 1990-01-01 00:00:00 | 男   |       1 |       1 |       1 |          2 |
| 05   | 周梅   | 1991-12-01 00:00:00 | 女   |       2 |       3 |    NULL |          3 |
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |       1 |       4 |       3 |          4 |
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |       3 |       5 |       3 |          5 |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |       4 |       6 |       5 |          6 |
| 06   | 吴兰   | 1992-03-01 00:00:00 | 女   |       5 |    NULL |       4 |          7 |
+------+--------+---------------------+------+---------+---------+---------+------------+
8 rows in set (0.00 sec)

 

18.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 c.cid as 课程编号, c.cname as 课程名称, A.*
from course as c,
(select cid,
    sum(case when score >= 85 then 1 else 0 end)/count(*) as 100_85,
    sum(case when score >= 70 and score < 85 then 1 else 0 end)/count(*) as 85_70,
    sum(case when score >= 60 and score < 70 then 1 else 0 end)/count(*) as 70_60,
    sum(case when score < 60 then 1 else 0 end)/count(*) as 60_0
from sc group by cid) as A
where c.cid = A.cid;
+--------------+--------------+------+--------+--------+--------+--------+
| 课程编号     | 课程名称     | cid  | 100_85 | 85_70  | 70_60  | 60_0   |
+--------------+--------------+------+--------+--------+--------+--------+
| 01           | 语文         | 01   | 0.0000 | 0.6667 | 0.0000 | 0.3333 |
| 02           | 数学         | 02   | 0.5000 | 0.1667 | 0.1667 | 0.1667 |
| 03           | 英语         | 03   | 0.3333 | 0.3333 | 0.0000 | 0.3333 |
+--------------+--------------+------+--------+--------+--------+--------+
3 rows in set (0.00 sec)

 

19.查询各科成绩前三名的记录

select * from (select *, rank() over(partition by cid order by score desc) as graderank from sc) A where A.graderank <= 3;
+------+------+-------+-----------+
| Sid  | Cid  | score | graderank |
+------+------+-------+-----------+
| 01   | 01   |  80.0 |         1 |
| 03   | 01   |  80.0 |         1 |
| 05   | 01   |  76.0 |         3 |
| 01   | 02   |  90.0 |         1 |
| 07   | 02   |  89.0 |         2 |
| 05   | 02   |  87.0 |         3 |
| 01   | 03   |  99.0 |         1 |
| 07   | 03   |  98.0 |         2 |
| 02   | 03   |  80.0 |         3 |
| 03   | 03   |  80.0 |         3 |
+------+------+-------+-----------+
10 rows in set (0.00 sec)

 

20.查询出只选修两门课程的学生学号和姓名

select student.sid,student.sname from sc,student where student.sid=sc.sid group by sid having count(*)=2;
+------+--------+
| sid  | sname  |
+------+--------+
| 05   | 周梅   |
| 06   | 吴兰   |
| 07   | 郑竹   |
+------+--------+
3 rows in set (0.00 sec)

 

21.查询名字中含有「风」字的学生信息

select * from student where sname like '%风%';
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |
+------+--------+---------------------+------+
1 row in set (0.00 sec)

 

22.查询 1990 年出生的学生名单

select * from student where year(sage)=1990;
+------+--------+---------------------+------+
| Sid  | Sname  | Sage                | Ssex |
+------+--------+---------------------+------+
| 01   | 赵雷   | 1990-01-01 00:00:00 | 男   |
| 02   | 钱电   | 1990-12-21 00:00:00 | 男   |
| 03   | 孙风   | 1990-05-20 00:00:00 | 男   |
| 04   | 李云   | 1990-08-06 00:00:00 | 男   |
| 08   | 王菊   | 1990-01-20 00:00:00 | 男   |
+------+--------+---------------------+------+
5 rows in set (0.00 sec)

 

23.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.*,max(sc.score) from student,sc,course,teacher where student.sid=sc.sid and sc.cid=course.cid and course.tid=teacher.tid and teacher.tname="张三";
+------+--------+---------------------+------+---------------+
| Sid  | Sname  | Sage                | Ssex | max(sc.score) |
+------+--------+---------------------+------+---------------+
| 01   | 赵雷   | 1990-01-01 00:00:00 | 男   |          90.0 |
+------+--------+---------------------+------+---------------+
1 row in set (0.00 sec)

 

24.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 *, DENSE_RANK() over (order by score desc) A from SC where Cid = (select Cid from Course where Tid=(select Tid from Teacher where Tname='张三'))) B where B.A=1;
+------+------+-------+---+
| Sid  | Cid  | score | A |
+------+------+-------+---+
| 01   | 02   |  90.0 | 1 |
+------+------+-------+---+
1 row in set (0.00 sec)

 

25.查询各学生的年龄,只按年份来算

select sname,year(now())-year(sage) as age from student;
+--------+------+
| sname  | age  |
+--------+------+
| 赵雷   |   30 |
| 钱电   |   30 |
| 孙风   |   30 |
| 李云   |   30 |
| 周梅   |   29 |
| 吴兰   |   28 |
| 郑竹   |   31 |
| 王菊   |   30 |
+--------+------+
8 rows in set (0.00 sec)

 

26.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 sname, timestampdiff(year, sage, now()) as age from student;
+--------+------+
| sname  | age  |
+--------+------+
| 赵雷   |   30 |
| 钱电   |   29 |
| 孙风   |   29 |
| 李云   |   29 |
| 周梅   |   28 |
| 吴兰   |   28 |
| 郑竹   |   30 |
| 王菊   |   30 |
+--------+------+
8 rows in set (0.01 sec)

 

27.查询本周过生日的学生

select * from student where week(now()) = week(sage);
Empty set (0.00 sec)

 

28.查询本月过生日的学生

select * from student where month(now()) = month(sage);
Empty set (0.00 sec)

 

29.查询下月过生日的学生

select * from student where month(now()+1)=month(sage);
Empty set (0.00 sec)

 

报错解决:

如果遇到以下报错:

ERROR 1055 (42000): Expression 1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'test.student.Sname' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

可以执行以下语句解决(mysql重启后失效):

SET GLOBAL sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';

作者:SyntaxError