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';
原文地址：https://segmentfault.com/a/1190000022279128
