一、创建数据库并使用数据库
--创建数据库
create database if not exists lyq;
--使用数据库
use lyq;
二、创建所需要的表,并插入数据
--创建表
-- 课程表
create table if not exists course(course_id int,course_name string,teacher_id int);
-- 分数表
create table if not exists score(student_id int,course_id int,score int);
-- 学生表
create table if not exists student(student_id int,student_name string,student_birth string,student_sex string);
-- 教师表
create table if not exists teacher(teacher_id int,
teacher_name string
);
--插入数据
-- 课程表
insert into table course values
(01,'语文',02),
(02,'数学',01),
(03,'英语',03);
-- 分数表
insert into table score values
(01,01,80),
(01,02,90),
(01,03,99),
(02,01,70),
(02,02,60),
(02,03,80),
(03,01,80),
(03,02,80),
(03,03,80),
(04,01,50),
(04,02,30),
(04,03,20),
(05,01,76),
(05,02,87),
(06,01,31),
(06,03,34),
(07,02,89),
(07,03,98);
-- 学生表
insert into table student values
(01,'赵雷', '1990-01-01','男'),
(02,'钱电', '1990-12-21','男'),
(03,'孙风', '1990-05-20','男'),
(04,'李云', '1990-08-06','男'),
(05,'周梅', '1991-12-01','女'),
(06,'吴兰', '1992-03-01','女'),
(07,'郑竹', '1989-07-01','女'),
(08,'王菊', '1990-01-20','女');
-- 教师表
insert into table teacher values (01,'张三'),(02,'李四'),(03,'王五');
三、难的一米的题目
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"01"课程比"02"课程成绩低的学生的信息及课程分数:
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:
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:
– (包括有成绩的和无成绩的)
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:
6.查询"李"姓老师的数量:
7.查询学过"张三"老师授课的同学的信息:
8.查询没学过"张三"老师授课的同学的信息:
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:
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:
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息:
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:
19、按各科成绩进行排序,并显示排名:
– row_number() over()分组排序功能(mysql没有该方法)
20、查询学生的总成绩并进行排名:
21、查询不同老师所教不同课程平均分从高到低显示:
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:
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:
25、查询各科成绩前三名的记录
26、查询每门课程被选修的学生数:
27、查询出只有两门课程的全部学生的学号和姓名:
28、查询男生、女生人数:
29、查询名字中含有"风"字的学生信息:
30、查询同名同性学生名单,并统计同名人数:
31、查询1990年出生的学生名单:
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:
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:
34、查询课程名称为"数学",且分数低于60的学生姓名和分数:
35、查询所有学生的课程及分数情况:
36、查询任何一门课程成绩在70分以上的学生姓名、课程名称和分数:
37、查询课程不及格的学生:
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:
39、求每门课程的学生人数:
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:
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、查询每门课程成绩最好的前三名:
43、统计每门课程的学生选修人数(超过5人的课程才统计):
– 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
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(周岁):
– 按照出生日期来算,当前月日 < 出生年月的月日则,年龄减一
47、查询本周过生日的学生:
48、查询下周过生日的学生:
49、查询本月过生日的学生:
50、查询12月份过生日的学生:
四、解答
--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 s3.*,s1.score,s2.score
from score s1 join score s2 join student s3
on s1.student_id=s2.student_id and s2.student_id = s3.student_id
where s1.course_id=1 and s2.course_id=2 and s1.score>s2.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 s3.*,s1.score,s2.score
from score s1 join score s2 join student s3
on s1.student_id=s2.student_id and s2.student_id = s3.student_id
where s1.course_id=1 and s2.course_id=2 and s1.score<s2.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
with t1 as
(select round(avg(s1.score)) r1,s1.student_id
from score s1
group by s1.student_id)
select t1.student_id,t2.student_name,t1.r1
from t1 join student t2
on t1.student_id=t2.student_id
where t1.r1>=60;
--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
with t1 as
(select round(avg(s1.score)) r1,s1.student_id
from score s1
group by s1.student_id)
select t1.student_id,t2.student_name,t1.r1
from student t2 left join t1
on t1.student_id=t2.student_id
where t1.r1<60 or t1.r1 is null;
--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
with t1 as
(select s.student_id,count(c.course_id),sum(s.score)
from score s join course c
on s.course_id=c.course_id
group by s.student_id)
select st.student_name,t1.*
from student st join t1
on st.student_id=t1.student_id;
--6.查询"李"姓老师的数量
select count(teacher_id) from teacher
where teacher_name like '李%';
--7.查询学过"张三"老师授课的同学的信息
with t1 as
(select teacher_id from teacher where teacher_name='张三'),
t2 as
(select c.course_id cid from course c join t1 on c.teacher_id=t1.teacher_id),
t3 as
(select s.student_id sid from score s join t2 on s.course_id=t2.cid)
select st.* from student st join t3 on st.student_id=t3.sid;
--8.查询没学过"张三"老师授课的同学的信息
select distinct s1.*
from student s1 left join score s3 on s1.student_id=s3.student_id
where not exists
(select s2.*
from score s1 join course c join teacher t1 join student s2 join (select teacher_id from teacher where teacher_name='张三') a
on s1.course_id = c.course_id and t1.teacher_id = c.teacher_id and s1.student_id = s2.student_id and a.teacher_id=t1.teacher_id
--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 distinct a.* from
(select s1.*,
count(s2.course_id) over(partition by s2.student_id) as num
from student s1 join score s2
on s1.student_id=s2.student_id
where s2.course_id!=3) a
where a.num=2;
--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
with a as
(select student_id from score where course_id=1),
b as
(select s.student_id sid from score s
join a on s.student_id=a.student_id
where s.student_id not in (
select student_id from score where course_id=2))
select distinct s.* from student s join b
on s.student_id=b.sid;
--11.查询没有学全所有课程的同学的信息
select st.* from student st
where st.student_id not in
(select a.sid tid from
(select s.student_id sid,count(1) num from score s
group by s.student_id) a
join
(select count(1) num from course) b
on a.num=b.num);
--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 st.* from student st
join
(select distinct sc.student_id sid from score sc
where sc.student_id!=1
and sc.course_id in
(select s.course_id cid from score s
where s.student_id=1)) a
on st.student_id=a.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 st.* from student st
join
(select a.sid cid from
(select student_id sid,count(course_id) num from score
where student_id!=1
group by student_id) a
join
(select count(s.course_id) cont from score s
where s.student_id=1) b
where a.num=b.cont) c
on st.student_id=c.cid;
--14.查询没学过"张三"老师讲授的任一门课程的学生姓名
select st.* from student st
where st.student_id not in
(select s1.student_id from score s1
where s1.course_id=2);
--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 * from
(select s1.student_id,count(s1.score) cont,avg(s1.score) acont from score s1
where s1.score<60
group by s1.student_id) a
where a.cont>=2;
--16.检索"01"课程分数小于60,按分数降序排列的学生信息
select st.*,s.score from score s
join student st
on st.student_id=s.student_id
where s.course_id=1
and s.score < 60
order by 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.score,
avg(s.score) over(partition by s.student_id) avgg
from score s
order by avgg;
--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
select s.course_id,c.course_name,
max(s.score),min(s.score),avg(s.score)
from score s
join course c
on s.course_id=c.course_id
group by s.course_id,c.course_name;
--19.按各科成绩进行排序,并显示排名
select s.course_id,st.student_name,s.score,
row_number() over(partition by s.course_id order by s.score desc) as ronum
from score s
join student st
on s.student_id=st.student_id;
--20.查询学生的总成绩并进行排名
select s.student_id,st.student_name,sum(s.score) ssum from score s
join student st
on st.student_id=s.student_id
group by s.student_id,st.student_name
order by ssum desc;
--21.查询不同老师所教不同课程平均分从高到低显示
select c.teacher_id,t.teacher_name,avg(s.score) avgg
from score s
join course c
join teacher t
on c.course_id=s.course_id and c.teacher_id=t.teacher_id
group by s.course_id,c.teacher_id,t.teacher_name
order by avgg 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
with t1 as
(select s.student_id sid,s.score sce,
row_number() over(partition by s.course_id order by s.score desc) as rnum
from score s)
select st.*,t1.sce,t1.rnum
from student st
join t1
on st.student_id=t1.sid
where t1.rnum in(2,3);
--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
with t1 as
(select s.student_id sid,avg(s.score) avgg
from score s
group by s.student_id)
select t1.sid,st.student_name,t1.avgg
from student st join t1
on st.student_id=t1.sid
order by t1.avgg desc;
--25.查询各科成绩前三名的记录
select a.* from
(select s.course_id,s.student_id,st.student_name,s.score,
row_number() over(partition by s.course_id order by s.score) as rnum
from score s join student st
on s.student_id=st.student_id) a
where a.rnum<=3;
--26.查询每门课程被选修的学生数
select count(s.student_id) from score s
group by s.course_id;
--27.查询出只有两门课程的全部学生的学号和姓名
with t1 as
(select s.student_id sid,count(s.student_id) num from score s
group by s.student_id)
select st.student_id,st.student_name from student st
join t1
on st.student_id=t1.sid
where t1.num=2;
--28.查询男生、女生人数
select s.student_sex,count(s.student_sex)
from student s
group by s.student_sex;
--29.查询名字中含有"风"字的学生信息
select * from student
where student_name like '%风%';
--30.查询同名同性学生名单,并统计同名人数
select student_name,count(*)
from student
group by student_name
having count(*)>1;
--31.查询1990年出生的学生名单
select * from student
where year(student_birth)=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 course_id,avg(score) as a
from score
group by course_id
order by a desc,course_id asc;
--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
with t1 as
(select student_id sid,avg(score) avgg
from score
group by student_id
having avg(score)>=85)
select t1.sid,st.student_name,t1.avgg
from t1
join student st
on t1.sid=st.student_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 st.student_name,s.score
from student st
join score s
on st.student_id=s.student_id
where s.course_id
in(select course_id from course where course_name='数学');
--35.查询所有学生的课程及分数情况
select st.student_name,c.course_name,s.score
from student st
join course c
join score s
on st.student_id=s.student_id and c.course_id=s.course_id;
--36.查询任何一门课程成绩在70分以上的学生姓名、课程名称和分数
with t1 as
(select student_id sid,course_id cid,score
from score
where score>70)
select st.student_name,c.course_name,t1.score
from t1
join student st
join course c
on st.student_id=t1.sid and t1.cid=c.course_id;
--37.查询课程不及格的学生
with
t1 as(
select distinct student_id
from score
where score <60)
select s.*
from student s join t1 on t1.student_id=s.student_id;
--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 s.student_id,st.student_name
from student st
join score s
on s.student_id=st.student_id and s.course_id=1
where s.score>=80;
--39.求每门课程的学生人数
select course_id,count(1) from score
group by course_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
with t1 as
(select teacher_id from teacher where teacher_name='张三'),
t2 as
(select c.course_id cid from course c join t1 on c.teacher_id=t1.teacher_id),
t3 as
(select s.student_id sid,s.score score from score s join t2 on s.course_id=t2.cid)
select st.*,t3.score from student st
join t3
on st.student_id=t3.sid
order by t3.score desc
limit 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 s1.student_id,s2.student_id,s1.course_id,s2.course_id,s1.score
from score s1 join score s2
on s1.student_id=s2.student_id
where s1.score=s2.score and s1.course_id!=s2.course_id;
--42.查询每门课程成绩最好的前三名
with t1 as
(select *,row_number() over(partition by course_id order by score) as rnum from score)
select * from t1
where t1.rnum<=3;
--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
with t1 as
(select course_id,count(1) cont
from score
group by course_id
order by course_id)
select * from t1
where t1.cont>5;
--44.检索至少选修两门课程的学生学号
with t1 as
(select student_id,count(1) cont from score group by student_id)
select * from student st
join t1
on st.student_id=t1.student_id
where t1.cont>=2;
--45.查询选修了全部课程的学生信息
select st.* from student st
where st.student_id in
(select a.sid tid from
(select s.student_id sid,count(1) num from score s
group by s.student_id) a
join
(select count(1) num from course) b
on a.num=b.num);
--46.查询各学生的年龄(周岁):
-- 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 *, cast(date_format(current_date(),'yyyy') as int)-cast(date_format(student_birth,'yyyy') as int)
from student;
--47、查询本周过生日的学生:
-- 找到下周一-1即为本周最后一天,开始时间为当前天
select *
from student
where unix_timestamp(cast(concat_ws('-',date_format(current_date(),'yyyy'),date_format(student_birth,'MM'),date_format(student_birth,'dd')) as date),'yyyy-MM-dd')
between unix_timestamp(current_date())
and unix_timestamp(date_sub(next_day(current_date(),'MON'),1),'yyyy-MM-dd');
--48、查询下周过生日的学生:
-- 找到下周的最后一天和最开始一天来算 next_day(current_date(),'SUNDAY'); -- 需要注意的是老外以星期天,开始需要+7
select *
from student
where unix_timestamp(cast(concat_ws('-',date_format(current_date(),'yyyy'),date_format(student_birth,'MM'),date_format(student_birth,'dd')) as date),'yyyy-MM-dd')
between unix_timestamp(next_day(current_date(),'MON'),'yyyy-MM-dd')
and unix_timestamp(date_add(next_day(current_date(),'SUN'),7),'yyyy-MM-dd');
--49、查询本月过生日的学生:
select *
from student
where month(student_birth) = month(current_date());
--50、查询12月份过生日的学生:
select *
from student
where month(student_birth)=12;