MySQL经典试题50道

表名和字段

–1.学生表 
Student(s_id,s_name,s_birth,s_sex) –学生编号,学生姓名, 出生年月,学生性别 
–2.课程表 
Course(c_id,c_name,t_id) – –课程编号, 课程名称, 教师编号 
–3.教师表 
Teacher(t_id,t_name) –教师编号,教师姓名 
–4.成绩表 
Score(s_id,c_id,s_score) –学生编号,课程编号,分数

测试数据表

--建表
--学生表
CREATE TABLE `Student`(
    `s_id` VARCHAR(20),
    `s_name` VARCHAR(20) NOT NULL DEFAULT '',
    `s_birth` VARCHAR(20) NOT NULL DEFAULT '',
    `s_sex` VARCHAR(10) NOT NULL DEFAULT '',
    PRIMARY KEY(`s_id`)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
--课程表
CREATE TABLE `Course`(
    `c_id`  VARCHAR(20),
    `c_name` VARCHAR(20) NOT NULL DEFAULT '',
    `t_id` VARCHAR(20) NOT NULL,
    PRIMARY KEY(`c_id`)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
--教师表
CREATE TABLE `Teacher`(
    `t_id` VARCHAR(20),
    `t_name` VARCHAR(20) NOT NULL DEFAULT '',
    PRIMARY KEY(`t_id`)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
--成绩表
CREATE TABLE `Score`(
    `s_id` VARCHAR(20),
    `c_id`  VARCHAR(20),
    `s_score` INT(3),
    PRIMARY KEY(`s_id`,`c_id`)
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
--插入学生表测试数据
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');
--课程表测试数据
insert into Course values('01' , '语文' , '02');
insert into Course values('02' , '数学' , '01');
insert into Course values('03' , '英语' , '03');
 
--教师表测试数据
insert into Teacher values('01' , '张三');
insert into Teacher values('02' , '李四');
insert into Teacher values('03' , '王五');
 
--成绩表测试数据
insert into Score values('01' , '01' , 80);
insert into Score values('01' , '02' , 90);
insert into Score values('01' , '03' , 99);
insert into Score values('02' , '01' , 70);
insert into Score values('02' , '02' , 60);
insert into Score values('02' , '03' , 80);
insert into Score values('03' , '01' , 80);
insert into Score values('03' , '02' , 80);
insert into Score values('03' , '03' , 80);
insert into Score values('04' , '01' , 50);
insert into Score values('04' , '02' , 30);
insert into Score values('04' , '03' , 20);
insert into Score values('05' , '01' , 76);
insert into Score values('05' , '02' , 87);
insert into Score values('06' , '01' , 31);
insert into Score values('06' , '03' , 34);
insert into Score values('07' , '02' , 89);
insert into Score values('07' , '03' , 98);

 

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 a.*,b.s_score as 01_score,c.s_score as 02_score from Student a
join Score b
on a.s_id=b.s_id and b.c_id='01'
left join Score c on a.s_id=c.s_id and c.c_id='02' or c.c_id=NULL where b.s_score>c.s_score;


2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数
select a.*,b.s_score as 02_socre,c.s_score as 01_score from Student a
join Score b
on a.s_id=b.s_id and b.c_id='02'
left join Score c on a.s_id=c.s_id and c.c_id='01' or c.c_id=NULL where b.s_score>c.s_score;





3、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 a.s_id,a.s_name,t.avg_socre from Student a join 
(select s_id,avg(s_score) as avg_socre from Score group by s_id having avg_socre>=60) t
on a.s_id=t.s_id;

4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩
select a.s_id,a.s_name,t.avg_socre from Student a join 
(select s_id,avg(s_score) as avg_socre from Score group by s_id having avg_socre<60) t
on a.s_id=t.s_id;


5、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
select a.s_id,a.s_name,b.course_num,b.grade_total from Student a
join (select s_id,count(c_id) as course_num,sum(s_score) as grade_total from Score group by s_id) b
on a.s_id=b.s_id

6、查询"李"姓老师的数量
select count(t_name) as li_num from Teacher where t_name like "李%"


7、查询学过"张三"老师授课的同学的信息
1) 查询出张三老师授课t_id
select t_id from Teacher where t_name="张三"

2) 查询出t_id对应的c_id
select c_id from Course where t_id in (select t_id from Teacher where t_name="张三")

3) 筛选出学过c_id的学生的s_id
select s_id from Score where c_id in(select c_id from Course where t_id in (select t_id from Teacher where t_name="张三"))

4) 关联Student获取信息
select a.* from Student a join (select s_id from Score where c_id in(select c_id from Course where t_id in (select t_id from Teacher where t_name="张三"))) b 
on a.s_id=b.s_id

8、查询没学过"张三"老师授课的同学的信息
1) 查询出张三老师授课t_id
select t_id from Teacher where t_name="张三"

2) 查询出t_id对应的c_id
select c_id from Course where t_id in (select t_id from Teacher where t_name="张三")

3) 筛选出学过c_id的学生的s_id
select s_id from Score where c_id in(select c_id from Course where t_id in (select t_id from Teacher where t_name="张三"))

4) 关联Student获取信息
select a.* from Student a where a.s_id not in (select s_id from Score where c_id in(select c_id from Course where t_id in (select t_id from Teacher where t_name="张三"))
);

9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息
select s_id from Score where c_id="01"
select s_id from Score where c_id="02"

select a.* from student a join
(select t1.s_id from (select s_id from Score where c_id="01")t1 join
(select s_id from Score where c_id="02")t2
on t1.s_id=t2.s_id)b
on a.s_id=b.s_id

10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息
select a.* from student a where a.s_id in(select s_id from Score where c_id="01")
and a.s_id not in(select s_id from Score where c_id="02")



11、查询没有学全所有课程的同学的信息
select count(c_id) as course_num from Course

select s_id,count(c_id) as num from Score
group by s_id having num<(select count(c_id) as course_num from Course)

select a.* from Student a join (select s_id,count(c_id) as num from Score
group by s_id having num<(select count(c_id) as course_num from Course))b
on a.s_id=b.s_id

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息
select c_id from Score where s_id="01"

select distinct s_id from Score where c_id in (select c_id from Score where s_id="01")
select a.* from Student a join (select distinct s_id from Score where c_id in (select c_id from Score where s_id="01")) b 
on a.s_id=b.s_id

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
select a.s_name from Student a where a.s_id not in (select s_id from Score where c_id in(select c_id from Course where t_id in (select t_id from Teacher where t_name="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 s_id,avg(s_score) as avg_score from Score where s_score<60
group by s_id
having count(c_id)>=2

select a.s_id,a.s_name,b.avg_score from Student a
join (select s_id,avg(s_score) as avg_score from Score where s_score<60
group by s_id
having count(c_id)>=2)b
on a.s_id=b.s_id

16、检索"01"课程分数小于60，按分数降序排列的学生信息
select a.*,b.s_score from Student a
join (select s_id,s_score from Score where c_id='01' and s_score<60)b
on a.s_id=b.s_id
order by b.s_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 s_id,avg(s_score) as avg_score from Score
group by s_id

select a.*,b.avg_score from Score a
join (select s_id,avg(s_score) as avg_score from Score
group by s_id)b
on a.s_id=b.s_id
order by b.avg_score 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






19、按各科成绩进行排序，并显示排名(实现不完全)
select a.*,@curRank := @curRank+1 as rank from Score a,
(select @curRank := 0)b
where a.c_id='01'
order by a.s_score desc
union
select a.*,@curRank := @curRank+1 as rank from Score a,
(select @curRank := 0)b
where a.c_id='02'
order by a.s_score desc
union
select a.*,@curRank := @curRank+1 as rank from Score a,
(select @curRank := 0)b
where a.c_id='03'
order by a.s_score desc



20、查询学生的总成绩并进行排名
select a.s_id,sum(a.s_score) as total_grade,@curRank := @curRank+1 as rank from Score a,
(select @curRank := 0)b
group by a.s_id
order by rank ;


21、查询不同老师所教不同课程平均分从高到低显示
select a.c_id,c.t_name,avg(a.s_score) as avg_score from Score a
join course b
on a.c_id=b.c_id
join Teacher c
on c.t_id=b.t_id
group by a.c_id
order by avg_score desc

22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩
select d.*,c.排名,c.s_score,c.c_id from (
select a.s_id,a.s_score,a.c_id,@i:=@i+1 as 排名 from score a,(select @i:=0)s where a.c_id='01'    
)c
left join student d on c.s_id=d.s_id
where 排名 BETWEEN 2 AND 3

xxx


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],[0-60]及所占百分比


24、查询学生平均成绩及其名次
select s_id,

select *,@r :=@r+1 as rank from Score,(select @r :=0)r
order by s_score desc

25、查询各科成绩前三名的记录
select s_id,c_id,s_score from Score where c_id='01'

union all
select s_id,c_id,s_score from Score where c_id='02'

26、查询每门课程被选修的学生数
select c_id,count(c_id) as course_num from Score group by c_id



27、查询出只有两门课程的全部学生的学号和姓名
select s_id,count(c_id) as course_num from Score group by s_id 
having course_num=2

select a.s_id,a.s_name from Student a
join (select s_id,count(c_id) as course_num from Score group by s_id 
having course_num=2)b
on a.s_id=b.s_id

28、查询男生、女生人数
select s_sex,count(s_sex) as num from Student 
group by s_sex

29、查询名字中含有"风"字的学生信息
select * from Student where s_name like "%风%" or "风%" or "%风"

30、查询同姓名同性学生名单，并统计同名人数
select a.s_name,a.s_sex,count(*) from student a  JOIN
student b on a.s_id !=b.s_id and a.s_name = b.s_name and a.s_sex = b.s_sex
GROUP BY a.s_name,a.s_sex

31、查询1990年出生的学生名单
select s_name,left(s_birth,4) from Student
where left(s_birth,4)='1990'

32、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 c_id,avg(s_score) from Score group by c_id
order by avg(s_score) desc,c_id 

33、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_id,avg(s_score) as avg_socre from Score
group by s_id
having avg_socre>=85

select a.s_id,a.s_name,b.avg_socre from Student a
join (select s_id,avg(s_score) as avg_socre from Score
group by s_id
having avg_socre>=85)b
on a.s_id=b.s_id

34、查询课程名称为"数学"，且分数低于60的学生姓名和分数
select c_id from Course where c_name='数学'

select s_id,s_score from Score where c_id=(select c_id from Course where c_name='数学' and s_score<60)

select a.s_id,a.s_name,b.s_score from Student a
join (select s_id,s_score from Score where c_id=(select c_id from Course where c_name='数学' and s_score<60))b
on a.s_id=b.s_id

35、查询所有学生的课程及分数情况；
废题

36、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 a.s_name,b.c_name,c.s_score from Course b left join
Score c on b.c_id=c.c_id left join Student a
on a.s_id=c.s_id where c.s_score>70

37、查询不及格的课程
select a.s_id,a.c_id,b.c_name,a.s_score from score a 
left join course b on a.c_id = b.c_id
where a.s_score<60

38、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 t.s_id,b.s_name from 
(select s_id from score 
where c_id='01' and s_score>=80)t
join student b
on t.s_id = b.s_id

39、求每门课程的学生人数
select a.c_id,b.c_name,count(a.c_id) from Score a
join Course b
on a.c_id=b.c_id
group by a.c_id


40、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 t_id from Teacher where t_name="张三"

select c_id from Course where t_id=(select t_id from Teacher where t_name="张三")

select max(s_score) as score from Score where c_id=(select c_id from Course where t_id=(select t_id from Teacher where t_name="张三"))
group by c_id

select s_id,s_score from Score where c_id=(select c_id from Course where t_id=(select t_id from Teacher where t_name="张三"))
and s_score=(select max(s_score) as score from Score where c_id=(select c_id from Course where t_id=(select t_id from Teacher where t_name="张三"))
group by c_id)

select a.*,b.s_score from Student a
join (select s_id,s_score from Score where c_id=(select c_id from Course where t_id=(select t_id from Teacher where t_name="张三"))
and s_score=(select max(s_score) as score from Score where c_id=(select c_id from Course where t_id=(select t_id from Teacher where t_name="张三"))
group by c_id))b
on a.s_id=b.s_id

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 a.s_id,a.c_id,a.s_score from Score a,Score b 
where a.c_id!=b.c_id and a.s_score=b.s_score

42、查询每门功成绩最好的前两名
xxx
select a.* from Score a
where (select count(1) from Score b where a.c_id=b.c_id and b.s_score>=a.s_score)<=2 
order by a.c_id

43、统计每门课程的学生选修人数（超过5人的课程才统计）。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 distinct c_id,count(c_id) from score
group by c_id
having count(c_id)>5
order by count(c_id) desc,c_id

44、检索至少选修两门课程的学生学号
select s_id,count(c_id) from Score group by s_id
having count(c_id)>=2


45、查询选修了全部课程的学生信息
select b.* from 
(select a.s_id,count(c_id) as total_course from score a
group by a.s_id
having count(c_id) = (select count(c_id) from course))t
join student b
on t.s_id = b.s_id


46、查询各学生的年龄
select s_birth,(DATE_FORMAT(NOW(),'%Y')-DATE_FORMAT(s_birth,'%Y') -
(case when DATE_FORMAT(NOW(),'%m%d')>DATE_FORMAT(s_birth,'%m%d') then 0 else 1 end)) as age
from student;

47、查询本周过生日的学生
select * from student where WEEK(DATE_FORMAT(NOW(),'%Y%m%d'))=WEEK(s_birth)

select WEEK(DATE_FORMAT(s_birth,'%Y%m%d')) from student


48、查询下周过生日的学生
select * from student where WEEK(DATE_FORMAT(NOW(),'%Y%m%d'))+1 =WEEK(s_birth)


49、查询本月过生日的学生
select * from student where month(DATE_FORMAT(now(),'%Y%m%d'))=month(s_birth)


50、查询下月过生日的学生
select * from student where month(DATE_FORMAT(now(),'%Y%m%d'))+1=month(s_birth)