mysql经典sql笔试题

百度云：表含数据 提取码：9psf

Mysql 版本 5.7.13

1、查询“01”课程比“02”课程成绩高的所有学生的学号和姓名：

select * from student where sid in 
(select s1.sid from (select * from sc  where cid="01")s1  
left join  (select * from sc where cid="02" ) s2 
on s1.sid = s2.sid  
where s1.score > s2.score);

2、查询平均成绩大于60分的同学的学号和平均成绩；

select avg(score) sco from sc  group by sid having sco > 60

3、查询所有同学的学号、姓名、选课数、总成绩

select st.sname,st.sid,count(s.cid),count(s.sid),sum(score) 
from student st left join sc s on st.sid = s.sid
GROUP BY s.sid

4、查询姓“李”的老师的个数；

select count(tid) from teacher where tname like "%李%"

5、查询没学过“张三”老师课的同学的学号、姓名；

select * from student stu 
where stu.sid not in 
(select sid from sc s inner join 
(select cid from teacher t 
left join course c on t.tid = c.tid 
where t.tname= "张三") c on s.cid = c.cid) ;

6、查询学过编号“01”并且也学过编号“02”课程的同学的学号、姓名；

select * from student st inner join
(select s1.sid from sc s1 inner join sc s2 on s1.sid = s2.sid where s1.cid = 01 and s2.cid = 02)res
on st.sid = res.sid;

#另一种解法
SELECT t.sid AS sid,student.sname 
FROM  (SELECT sid FROM sc GROUP BY sid HAVING COUNT(IF(cid = "01",score,NULL)) > 0 AND COUNT(IF(cid = "02",score,NULL)) > 0) AS t
LEFT JOIN student ON t.sid = student.sid;

7、查询学过“张三”老师所教的课的同学的学号、姓名；

select stu.sid,stu.sname from student stu inner join (select sid from sc s inner join 
( select cid from teacher t left join course c on t.tid = c.tid  where t.tname= "张三") c on s.cid = c.cid) res on stu.sid= res.sid ;

8、查询课程编号“01”的成绩比课程编号“02”课程低的所有同学的学号、姓名；

select st.sid,st.sname 
from student st inner join (select s1.sid from sc s1 inner join sc s2 on s1.sid = s2.sid where s1.cid = 01 and s2.cid = 02 and s1.score < s2.score)res
on st.sid = res.sid;

9、查询所有课程成绩小于60分的同学的学号、姓名；

select st.sid,st.sname 
from student st inner join 
(select sid from sc group by sid having count(if(score<60,1,NULL))>0)res 
on st.sid = res.sid;

10、查询没有学全所有课的同学的学号、姓名；

select st.sid,st.sname 
from student st inner join 
(select sid  from sc group by sid having count(cid) < (select count(cid) from course)) res 
on st.sid = res.sid

11、查询至少有一门课与学号为“01”的同学所学相同的同学的学号和姓名；

select st.sid,st.sname from student st 
inner join (SELECT distinct c2.sid	FROM (SELECT cid FROM sc WHERE sid = "01") c1 LEFT JOIN (SELECT sid,cid FROM sc WHERE sid != "01") c2 ON c1.cid = c2.cid ) res 
on st.sid = res.sid

12、查询和"01"号的同学学习的课程完全相同的其他同学的学号和姓名

select st.sid,st.sname 
from student st inner join  (select c2.sid from (SELECT GROUP_CONCAT(cid) res FROM sc WHERE sid = "01") c1  
inner JOIN (SELECT GROUP_CONCAT(cid) res,sid FROM sc WHERE sid != "01" group by sid ) c2 ON c1.res = c2.res) res 
on st.sid = res.sid

13、把“SC”表中“张三”老师教的课的成绩都更改为此课程的平均成绩

update sc s set score =(select * from ( select avg(score) from sc where cid=
(select c.cid from teacher t inner join course c on t.tid = c.tid where tname = "张三")) res)
 where cid = (select c.cid from teacher t inner join course c on t.tid = c.tid where tname = "张三" )

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.sid,st.sname 
from student st inner join (select * from sc group by sid having 
count(if((select c.cid from teacher t inner join course c on t.tid = c.tid where tname = "张三")=cid,1,NULL))=0)res 
on st.sid = res.sid

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 st.sid,st.sname ,res.avgScore 
from student st inner join 
(select sid,avg(score)avgScore from sc group by sid having count(if(score<=60,1,NULL))>=2 )res
on st.sid = res.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 st.* from student st 
inner join (select sid from sc where cid = 01 and score <60 order by score desc)res
on st.sid = res.sid

17、按平均成绩从高到低显示所有学生的平均成绩

select st.sid,st.sname,avg(s.score)avgScore 
from student st left join sc s on  st.sid = s.sid
group by st.sid order by avgScore 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

select s.cid 课程ID ,c.cname 课程name ,max(s.score) 最高分,min(s.score)最低分,avg(s.score)平均分,
count(if(s.score > 60,s.sid,NULL)) / COUNT(s.sid)  及格率
from sc s inner join course c on s.cid = c.cid
group by s.cid

19、按各科平均成绩从低到高和及格率的百分数从高到低顺序

select avg(score)score,cid, COUNT(IF(score > 60,sid,NULL)) / COUNT(sid) passRate
from sc group by cid order by score asc,passRate DESC

20、查询学生的总成绩并进行排名

select res.score,stu.sname from student stu inner join 
(select sum(score) score,sid from sc group by sid )res
on stu.sid = res.sid
order by res.score desc;

21、查询不同老师所教不同课程平均分从高到低显示

select avg(score)score,cid from sc group by cid order by 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

23、统计各科成绩各分数段人数：课程编号，课程名称，[100-85]，[84-70]，[69-60]，[0-60]及所占百分比

select c.cid, c.cname,
 ROUND(sum(case when s.score<=100 and s.score>=85 then 1 else 0 end) / count(s.cid) *100,2) as '[100-85]',
 ROUND(sum(case when s.score<=84 and s.score>=70 then 1 else 0 end) / count(s.cid) *100,2)as '[84-70]',
 ROUND(sum(case when s.score<=69 and s.score>=60 then 1 else 0 end) / count(s.cid) *100,2)as '[69-60]',
 ROUND(sum(case when s.score<60 then 1 else 0 end) / count(s.cid) *100,2)as '[0-60]'
 from sc s inner join course c on s.cid = c.cid
 group by s.cid

24、查询学生平均成绩及其名次

select @rownum := @rownum+1 as num,avg(s.score) score from sc s,(select @rownum := 0)temp
group by s.sid order by s.score desc

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

select count(sid) num from sc group by cid

27、查询出只选修一门课程的全部学生的学号和姓名

select count(sid)cou,sid from sc group by sid having cou<=1

28、查询男生，女生人数

select 
sum(case ssex when '男' then 1 else 0 end) '男',
sum(case ssex when '女' then 1 else 0 end) '女'
from student

29、查询名字中含有“风”字的学生信息

select * from student where sname like "%风%"

30、查询同名同性学生名单，并统计同名人数

select sname,count(1)  from student group by sname having count(1) > 1

31、查询1990年出生的学生名单（注：Student表中Sage列的类型是datetime）

select * from student where year(sage)=1990

32、查询每门课程的平均成绩，结果按平均成绩升序排列，平均成绩相同时，按课程号降序排列

select avg(score)score,cid 
from sc group by cid order by score asc, cid desc

33、查询课程编号为“ 01”且课程成绩在60分以上的学生的学号和姓名；

select * from student s inner join 
(select sid from sc where cid = 01 and score >60) res
 on s.sid = res.sid

34、查询选修“张三”老师所授课程的学生中，成绩最高的学生姓名及其成绩

select sname,res.score from student s inner join 
(select sid,score from sc where cid = 
(select c.cid from teacher t,course c where t.tname = "张三"and c.tid=t.tid) 
order by score desc limit 0,1)res on res.sid = s.sid

35、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 cid,COUNT(cid)sum from sc group by cid having  sum > 5 order by sum desc ,cid asc

36、检索至少选修两门课程的学生学号

select sid from sc group by sid having count(sid) >= 2

37、查询选修了全部课程的学生信息

select * from sc group by sid having COUNT(sid) = (select count(cid) from course)