目录
一、数据表介绍
二、练习题
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
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、练习题
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 s.*, sc1.score, sc2.score
from student s
join SC sc1
on s.SId = sc1.SId
join SC sc2
on sc1.SId = sc2.CId and sc1.CId = "01" and sc2.CId = "02"
where sc1.score > sc2.score;
2. 查询同时存在" 01 "课程和" 02 "课程的情况
select s1.SId, s1.score,s2.score
from (select SId, score from SC where CId ="01") s1,
(select SId, score from SC where CId ="02") s2
where s1.SId = s2.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 SC a
left join SC b
on a.SId = b.SId and b.CId = "02"
where a.CId = "01";
4. 查询不存在" 01 "课程但存在" 02 "课程的情况
select *
from (select * from SC s where s.CId = "02") as a
where a.SId not in (select SId from SC s where s.CId = "01");
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 SC.SId, s.Sname, AVG(score)
from student s, SC
where s.SId = SC.SId
group by SC.SId
having AVG(score) >= 60;
6. 查询在 SC 表存在成绩的学生信息
select *
from student
where student.SId in (select SId from SC);
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, b.cnt, b.sum_s
from student s
left join (select SId, count(CId) as cnt, sum(score) as sum_s
from SC group by SId) as b
on s.SId = b.SId;
8. 查有成绩的学生信息
select *
from student
where SId in (select SId from SC group by 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 s.*, Tname
from student s
inner join(
select SC.*, Tname
from SC
inner join(
select course.*, Tname
from course
inner join teacher as th
on course.TId = th.TId) as a
on SC.CId = a.CId) as b
on s.SId = b.SId
where Tname = '张三';
11. 查询没有学全所有课程的同学的信息
select s.*
from student s
inner join(
select SId, count(CId) as cnt
from SC
group by SId
having cnt < (select count(CId) from course)) as a
on s.SId = a.SId;
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 s.*
from student s
inner join (
select *
from SC
where CId in(
select CId
from SC
where SId = "01")) as b
on s.SId = b.SId;
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 s.*
from student s
inner join (
select SId
from SC
where SId not in (
select SId
from SC
where CId not in (
select CId
from SC
where SId = "01")) and SId != "01"
group by SId
having count(CId) = (select count(CId) from SC where SId = "01")) as a
on s.SId = a.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 Sname
from student s
where SId not in (
select SId
from SC
left join course cou
on SC.CId = cou.CId
inner join teacher th
on cou.TId = th.TId
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 b.SId, s.Sname, avg_sc
from (
select SC.SId, AVG(score) as avg_sc
from SC
inner join(
select SId
from SC
where score < 60
group by SId
having count(CId) >= 2) as a
on SC.SId = a.SId
group by SC.SId) as b
left join student s
on b.SId = s.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 s.*, a.score
from student s
right join(
select SId, score
from SC
where CId = "01" and score <60) as a
on s.SId = a.SId
order by a.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 a.SId, a.CId, a.Score, avg_sc
from (
select s.SId, SC.CId, SC.Score
from student s
left join SC
on s.SId = SC.SId) as a
left join (
select SId, AVG(score) as avg_sc
from SC
group by SId) as b
on a.SId = b.SId
order by b.avg_sc 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 a.*, b.Cname
from(
select CId,
count(*) as 选修人数,
max(score) as 最高分,
min(score) as 最低分,
avg(score) as 平均分,
sum(case when score >= 60 then 1 else 0 end) / count(*) as 及格率,
sum(case when score >= 70 and score < 80 then 1 else 0 end) / count(*) as 中等率,
sum(case when score >= 80 and score < 90 then 1 else 0 end) / count(*) as 优良率,
sum(case when score >= 90 then 1 else 0 end) / count(*) as 优秀率
from SC
group by CId
order by count(*) desc, CId asc) as a
left join course as b
on a.CId = b.CId;
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 *, row_number()
over (partition by CId order by score desc) as 排名
from SC;
20. 按各科成绩进行排序，并显示排名， Score 重复时合并名次
select *, rank()
over (partition by CId order by score desc) as 排名
from SC;
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 *, rank()
over (order by sum_s desc) as 排名
from (select SId, sum(score) as sum_s
from SC
group by SId) as a;
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
select *,dense_rank()
over (order by sum_sc desc) as 排名
from(select SId, sum(score) as sum_sc
from SC
group by SId) as a;
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
select b.*, a.Cname
from course as a
right join(
select CId,
concat(sum(case when score > 0 and score < 60 then 1 else 0 end) / count(*) * 100, '%') as '[0-60]',
concat(sum(case when score >= 60 and score < 70 then 1 else 0 end) / count(*) * 100, '%') as '[60-70]',
concat(sum(case when score >= 70 and score < 85 then 1 else 0 end) / count(*) * 100, '%') as '[70-85]',
concat(sum(case when score >= 85 and score <= 100 then 1 else 0 end) / count(*) * 100, '%') as '[85-100]'
from SC
group by CId) as b
on a.CId = b.CId;
24. 查询各科成绩前三名的记录
select *
from(
select *,dense_rank()
over (partition by CId order by score desc) as rnk
from SC) as a
where rnk <= 3;
25. 查询每门课程被选修的学生数
select CId, count(*) as 学生数
from SC
group by CId;
26. 查询出只选修两门课程的学生学号和姓名
select a.SId, s.Sname
from student s
right join(
select SId, count(*) as 课程数
from SC
group by SId
having 课程数 = 2) as a
on s.SId = a.SId;
27. 查询男生、女生人数
select Ssex, count(*) as num
from student
group by Ssex;
28. 查询名字中含有「风」字的学生信息
select *
from student
where Sname like "%风%";
29. 查询同名同性学生名单，并统计同名人数
select Sname, Ssex, count(*) as 同名人数
from (
select s.*
from student s
inner join student a
on s.Sname = a.Sname and s.Ssex = a.Ssex and s.SId != a.SId) as a
group by Sname, Ssex;
30. 查询 1990 年出生的学生名单
select *
from student
where year(Sage) = "1990";
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
select CId, avg(score) as avg_sc
from SC
group by CId
order by avg_sc desc, CId asc;
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
select s.SId, s.Sname, avg_sc
from student s
right join(
select SId, avg(score) as avg_sc
from SC
group by SId
having avg_sc >= 85) as a
on s.SId = a.SId;
33. 查询课程名称为「数学」，且分数低于 60 的学生姓名和分数
select s.SId, s.Sname, SC.CId, SC.score
from SC
left join student s
on SC.SId = s.SId
where CId = (
select CId
from course
where Cname = "数学") and score < 60;
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）
select *
from student s
left join SC
on s.SId = SC.SId;
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
select s.Sname, c.Cname, SC.score
from SC
left join course as c
on SC.CId = c.CId
left join student s
on SC.SId = s.SId
where SC.score > 70;
36. 查询不及格的课程
select *
from course
where CId in (
select distinct CId
from SC
where score < 60);
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
select s.SId, s.Sname
from student s
join SC
on s.SId = SC.SId
where SC.CId = "01" and SC.score > 80;
38. 求每门课程的学生人数
select CId, count(*)
from SC
group by CId;
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
select s.*, SC.score
from student s, teacher th, course c, SC
where th.TId = c.TId
and SC.SId = s.SId
and SC.CId = c.CId
and th.Tname = "张三"
order by score desc
limit 1;
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
select s.*, SC.score
from student s
join SC
on s.SId = SC.SId
join course c
on SC.CId = c.cId
join teacher th
on c.TId = th.TId
where th.Tname = "张三"
order by score desc
limit 0,1;
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
select distinct s.SId, s.Sname, a.CId, a.score, b.CId, b.score
from student s
join SC a
on a.SId = s.SId
join SC b
on b.SId = s.SId
where a.CId != b.CId and a.score = b.score;
42. 查询每门功成绩最好的前两名
select s.*, a.*
from student s
left join (
select SC.SId, SC.score, row_number()
over (partition by SC.CId) ranks
from SC) as a
on s.SId = a.SId
where a.ranks <= 2;
43. 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(*)
from SC
join course c
on SC.CId = c.CId
group by SC.CId
having count(*) > 5;
44. 检索至少选修两门课程的学生学号
select s.SId
from SC
join student s
on SC.SId = s.SId
group by SC.SId
having count(*) >= 2;
45. 查询选修了全部课程的学生信息
select s.*
from SC
join student s
on SC.SId = s.SId
group by SC.SId
having count(*) = (select count(*) from course);
46. 查询各学生的年龄，只按年份来算
select s.*, year(now()) - year(s.Sage) 年龄
from student s;
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
select s.*, timestampdiff(year, s.Sage, curdate()) 年龄
from student s;
48. 查询本周过生日的学生
select s.*
from student s
where weekofyear(s.Sage) = weekofyear(now());
49. 查询下周过生日的学生
select s.*
from student s
where weekofyear(s.Sage) = weekofyear(now()) + 1;
50. 查询本月过生日的学生
select s.*
from student s
where month(s.Sage) = month(now());
51. 查询下月过生日的学生
select s.*
from student s
where month(s.Sage) = month(now()) + 1;
参考文章
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