MySQL 练习题

创建表

 --1.学生表
Student(Sno,Sname,Sage,Ssex) --Sno 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别

create table Student(
Sno varchar(10),
Sname varchar(10),
Sage datetime,
Ssex nvarchar(10)
) ;

--创建测试数据
insert into Student values('01' , '赵四' , '1994-01-01' , '男');
insert into Student values('02' , '钱贵' , '1996-12-21' , '男');
insert into Student values('03' , '孙三' , '1994-05-20' , '男');
insert into Student values('04' , '李一' , '1993-08-06' , '男');
insert into Student values('05' , '周吴' , '1994-12-01' , '女');
insert into Student values('06' , '吴理' , '1995-03-01' , '女');
insert into Student values('07' , '郑八' , '1996-07-01' , '女');
insert into Student values('08' , '王玖' , '1995-01-20' , '女');

--2.课程表 
Course(Cno,Cname,Tno) --Cno --课程编号,Cname 课程名称,Tno 教师编号

create table Course(
Cno varchar(10),
Cname varchar(10),
Tno varchar(10)
);

--创建测试数据
insert into Course values('01' , '语文' , '02');
insert into Course values('02' , '数学' , '03');
insert into Course values('03' , '英语' , '01');
 

--3.教师表 
Teacher(Tno,Tname,Ssex) --T 教师编号,Tname 教师姓名,Tsex 老师性别

create table Teacher(
Tno varchar(10),
Tname varchar(10),
Tsex varchar(10)

);
--创建测试数据
insert into Teacher values('01' , '张老师', '男');
insert into Teacher values('02' , '李老师'，'女');
insert into Teacher values('03' , '王老师'，'男');

--4.成绩表 
SC(Sno,Cno,score) --Sno 学生编号,Cno 课程编号,score 分数

create table SC(
Sno varchar(10),
Cno varchar(10),
score decimal(18,1)
);

--创建测试数据
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);
insert into SC values('08' , '01' , 88);
insert into SC values('08' , '02' , 90);
insert into SC values('08' , '03' , 87);

 题目（点击看答案）

--1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数。 （答案）

--2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数。 (略)

--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。（答案）

--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。(略)

--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。（答案）

--6、查询"李"姓老师的数量。（答案）

--7、查询学过"张老师"授课的同学的信息。（答案）

--8、查询没学过"张老师"授课的同学的信息。（答案）

--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。（答案）

--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。（答案）

--11、查询没有学全所有课程的同学的信息。（答案）

--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。（答案）

--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。（答案）

--14、查询没学过"张老师"讲授的任一门课程的学生姓名。（答案）

--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。（答案）

--16、检索"01"课程分数小于60，按分数降序排列的学生信息。（答案）

--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。（答案）

--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（答案）

--19、按各科成绩进行排序，并显示排名。（答案）

--20、查询学生的总成绩并进行排名。（答案）

--21、查询不同老师所教不同课程平均分从高到低显示。（答案）

--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。（答案）

--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。（答案）

--24、查询学生平均成绩及其名次。（答案）

--25、查询各科成绩前三名的记录。（答案）

--26、查询每门课程被选修的学生数。（答案）

--27、查询出只有两门课程的全部学生的学号和姓名。（答案）

--28、查询男生、女生人数。（略）

--29、查询名字中含有"风"字的学生信息。（略）

--30、查询同名同性学生名单，并统计同名人数。（答案）

--31、查询1994年出生的学生名单(注：Student表中Sage列的类型是datetime)。（答案）

--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。（答案）

--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。（答案）

--34、查询课程名称为"数学"，且分数低于60的学生姓名和分数。（答案）

--35、查询所有学生的课程及分数情况。（答案）

--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。（答案）

--37、查询不及格的课程。（略）

--38、查询课程编号为02且课程成绩在80分以上的学生的学号和姓名。（答案）

--39、求每门课程的学生人数。（略）

--40、查询选修"张老师"所授课程的学生中，成绩最高的学生信息及其成绩。（答案）

--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。（答案）

--42、查询每门功成绩最好的前两名。（略）

--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。（答案）

--44、检索至少选修两门课程的学生学号。（略）

--45、查询选修了全部课程的学生信息。（略）

--46、查询各学生的年龄。（答案）

--47、查询本周过生日的学生。（答案）

--48、查询下周过生日的学生。（略）

--49、查询本月过生日的学生。（答案）

--50、查询下月过生日的学生。（答案）

答案：

1、

SELECT stu.*
,sc01.score AS '01分数'
,sc02.score AS '02分数'
FROM student stu
INNER JOIN sc sc01
ON stu.Sno=sc01.Sno AND sc01.Cno='01'
INNER JOIN sc sc02
ON stu.Sno=sc02.Sno AND sc02.Cno='02'
WHERE sc02.score > sc01.score ;

3、

SELECT stu.Sno
,stu.sname
,AVG(sc.score) AS '平均分'
FROM student stu
INNER JOIN sc
ON stu.Sno=sc.Sno
GROUP BY stu.Sno
HAVING AVG(sc.score)>=60;

5、

SELECT stu.Sno
,stu.sname
,COUNT(sc.Cno) AS '选课总数'
,SUM(sc.score) AS '总成绩'
FROM student  stu
INNER JOIN sc
ON stu.Sno=sc.Sno
GROUP BY stu.Sno

6、

SELECT COUNT(*) FROM teacher WHERE Tname LIKE '李%' ;

7、

SELECT stu.*
FROM student stu
INNER JOIN sc
ON stu.Sno=sc.Sno
INNER JOIN course c
ON sc.Cno=c.Cno
INNER JOIN teacher t
ON c.Tno=t.Tno
WHERE t.Tname ='张老师' 

8、

SELECT stu.*
FROM student stu
LEFT JOIN sc
ON stu.Sno=sc.Sno
WHERE NOT EXISTS(
              SELECT *
              FROM course c
              INNER JOIN teacher t
              ON c.Tno=t.Tno
              INNER JOIN sc
              ON sc.Cno=c.Cno
              WHERE t.Tname='张老师'
              AND sc.Sno=stu.Sno
       )
GROUP BY Sno；

9、

SELECT stu.*
FROM student stu
INNER JOIN sc sc01
ON stu.Sno=sc01.Sno AND sc01.Cno='01'
INNER JOIN sc sc02
ON stu.Sno=sc02.Sno AND sc02.Cno='02'

10、

select stu.*
from student stu
LEFT JOIN sc sc01
on stu.Sno=sc01.Sno and sc01.Cno='01'
LEFT JOIN sc sc02
on stu.Sno=sc02.Sno and sc02.Cno='02'
where sc01.Cno='01' and sc02.Cno='02' is NULL ;

11、 

SELECT s.*
FROM student s
LEFT JOIN sc
ON s.Sno=sc.Sno
LEFT JOIN (
SELECT COUNT(1) anum FROM course
) c
ON 1=1
GROUP BY 1,2,3,4
HAVING MAX(c.anum)>COUNT(sc.Cno) ;

12、

SELECT s.*
FROM student s
INNER JOIN sc b
ON s.Sno=b.Sno
WHERE EXISTS(
    SELECT 1 FROM sc WHERE Sno='01' AND Cno=b.Cno
)
GROUP BY Sno;

13、

SELECT a.*
,COUNT(b.Cno) AS anum
,SUM(CASE WHEN EXISTS(SELECT 1 FROM sc WHERE Sno='01' AND Cno=b.Cno)THEN 1 ELSE 0 END) AS snum
,MAX(c.num1) AS num1
FROM student a
INNER JOIN sc b
ON a.Sno=b.Sno
INNER JOIN (SELECT COUNT(1) AS num1 FROM sc WHERE Sno='01') c
ON 1=1
GROUP BY 1
HAVING anum=snum AND anum=num1 ;

14、

SELECT a.*
FROM student a
LEFT JOIN(
       SELECT a.s
       FROM student a
       LEFT JOIN sc b
       ON a.Sno=b.Sno
       LEFT JOIN course c
       ON b.Cno=c.Cno
       LEFT JOIN teacher d
       ON c.Tno=d.Tno AND d.Tname='张老师'
       WHERE d.Tno IS NOT NULL
       )b
ON a.s=b.s
WHERE b.s IS NULL ;

15、

SELECT a.Sno
,a.sname
,AVG(b.score)
FROM student a
INNER JOIN sc b
ON a.Sno=b.Sno
GROUP BY 1,2
HAVING SUM(CASE WHEN b.score>=60 THEN 0 ELSE 1 END)>=2

16、

SELECT a.*
,b.score
FROM student a
INNER JOIN sc b
ON a.Sno=b.Sno
WHERE b.Cno='01' AND b.score < 60
ORDER BY b.score DESC ;

17、

SELECT a.*
,SUM(CASE WHEN b.Cno='01' THEN b.score ELSE 0 END) AS s01
,SUM(CASE WHEN b.Cno='02' THEN b.score ELSE 0 END) AS s02
,SUM(CASE WHEN b.Cno='03' THEN b.score ELSE 0 END) AS s03
,AVG(CASE WHEN b.score IS NULL THEN 0 ELSE b.score END) avs
FROM student a
LEFT JOIN sc b
ON a.Sno=b.Sno
GROUP BY 1
ORDER BY avs DESC ;

18、

SELECT a.Cno
,a.Cname
,MAX(b.score)
,MIN(b.score)
,AVG(b.score)
,SUM(CASE WHEN b.score>=60 THEN 1 ELSE 0 END)/COUNT(1)
,SUM(CASE WHEN b.score>=70 AND b.score<80 THEN 1 ELSE 0 END)/COUNT(1)
,SUM(CASE WHEN b.score>=80 AND b.score<90 THEN 1 ELSE 0 END)/COUNT(1)
,SUM(CASE WHEN b.score>=90 THEN 1 ELSE 0 END)/COUNT(1)
FROM course a
INNER JOIN sc b
ON a.Cno=b.Cno
GROUP BY 1,2 ;

19、

SET @r:=0;
SELECT a.Cname,a.score,@r:=@r+1
FROM(
SELECT c.*,sc.score
FROM course c
INNER JOIN sc
ON c.Cno=sc.Cno
WHERE c.Cno='01'
ORDER BY sc.Cno DESC
)a

20、

SET @r:=0;
SELECT a.*, @r:=@r+1 as '总成绩排名'
FROM (
SELECT sc.Sno, SUM(sc.score) as '总成绩'
FROM sc
GROUP BY sc.Sno 
ORDER BY SUM(sc.score) DESC
)a

21、

SELECT a.*
,b.Cname
,AVG(c.score) as core
FROM teacher a
INNER JOIN course b
ON a.Tno=b.Tno
INNER JOIN sc c
ON b.Cno=c.Cno
GROUP BY 1
ORDER BY core DESC ;

22、

SELECT a.*,b.Cname,b.score
FROM student a
INNER JOIN (
     SELECT a.*,
     c.Cname,
     COUNT(b.Cno)+1 AS tp 
     FROM sc a 
     LEFT JOIN sc b 
     ON a.Cno=b.Cno AND a.score<b.score 
     LEFT JOIN course c 
     ON a.Cno=c.Cno 
     GROUP BY 1 
     HAVING COUNT(b.Cno)+1 IN(2,3) 
     
) b
ON a.Sno=b.Sno

23、

SELECT a.Cno
,a.Cname
,SUM(CASE WHEN b.score<=100 AND b.score>85 THEN 1 ELSE 0 END) AS '[100-85]'
,SUM(CASE WHEN b.score<=85  AND b.score>70 THEN 1 ELSE 0 END) AS '[85-70]'
,SUM(CASE WHEN b.score<=70  AND b.score>60 THEN 1 ELSE 0 END) AS '[70-60]'
,SUM(CASE WHEN b.score<=60  AND b.score>0   THEN 1 ELSE 0 END) AS '[60-0]'
,SUM(CASE WHEN b.score<=100 AND b.score>85 THEN 1 ELSE 0 END)/COUNT(1) AS '[100-85]%'
,SUM(CASE WHEN b.score<=85  AND b.score>70 THEN 1 ELSE 0 END)/COUNT(1) AS '[85-70]%'
,SUM(CASE WHEN b.score<=70  AND b.score>60 THEN 1 ELSE 0 END)/COUNT(1) AS '[70-60]%'
,SUM(CASE WHEN b.score<=60  AND b.score>0   THEN 1 ELSE 0 END)/COUNT(1) AS '[60-0]%'
FROM course a
INNER JOIN sc b
ON a.Cno=b.Cno
GROUP BY 1,2 

24、

SELECT a.*,COUNT(b.Sno)+1
FROM (
  SELECT a.*,AVG(CASE WHEN b.score IS NULL THEN 0 ELSE b.score END) AS ascore 
  FROM student a 
  LEFT JOIN sc b ON a.Sno=b.Sno 
  GROUP BY 1
)a
LEFT JOIN(
  SELECT a.*,AVG(CASE WHEN b.score IS NULL THEN 0 ELSE b.score END) AS ascore 
  FROM student a LEFT JOIN sc b ON a.Sno=b.Sno 
  GROUP BY 1
)b 
ON a.ascore<b.ascore 
GROUP BY 5 DESC

25、

SELECT a.*,COUNT(b.Cno)+1 AS ascore
FROM sc a
LEFT JOIN sc b
ON a.Cno=b.Cno AND a.score<b.score
GROUP BY 1,2,3
HAVING ascore<=3
ORDER BY a.Cno,ascore

26、

SELECT a.*,COUNT(b.Sno)
FROM course a
LEFT JOIN sc b
ON a.Cno=b.Cno
GROUP BY 1,2,3 

27、

SELECT a.Sno,a.Sname
FROM student a
LEFT JOIN sc b
ON a.Sno=b.Sno
GROUP BY 1
HAVING COUNT(b.Cno)=2

30、

SELECT Sname
,Ssex
,COUNT(1)
FROM student
GROUP BY 1,2
HAVING COUNT(1) > 1 

31、

SELECT * FROM student WHERE YEAR(sage)=1994

32、

SELECT a.*
,AVG(b.score) AS ascore
FROM course a
LEFT JOIN sc b
ON a.Cno=b.Cno
GROUP BY 1,2,3
ORDER BY ascore DESC ,a.Cno 

33、

SELECT a.*
,AVG(b.score) AS ascore
FROM student a
LEFT JOIN sc b
ON a.Sno=b.Sno
GROUP BY 1
HAVING ascore>=85

34、

SELECT c.*
FROM course a
LEFT JOIN sc b
ON a.Cno=b.Cno
LEFT JOIN student c
ON b.Sno=c.Sno
WHERE a.Cname='数学'
AND b.score < 60 

35、

SELECT *
FROM sc a
INNER JOIN student b
ON a.Sno=b.Sno
INNER JOIN course c
ON a.Cno=c.Cno

36、

SELECT b.Sname
,c.Cname
,a.score
FROM sc a
INNER JOIN student b
ON a.Sno=b.Sno
INNER JOIN course c
ON a.Cno=c.Cno
WHERE a.score > 70

38、

SELECT a.Sno,a.Sname
FROM student a
INNER JOIN sc b
ON a.Sno=b.Sno
WHERE b.Cno='02' AND b.score > 80

40、

SELECT a.*,b.score
FROM student a
INNER JOIN sc b
ON a.Sno=b.Sno
INNER JOIN(
  SELECT c.Cno,MAX(c.score) AS maxscore
  FROM teacher a
  INNER JOIN course b
  ON a.Tno=b.Tno
  INNER JOIN sc c
  ON b.Cno=c.Cno
  WHERE a.Tname='张老师'
  GROUP BY Cno
)c
ON b.Cno=c.Cno AND b.score=c.maxscore

41、

SELECT a.Sno,a.Cno,a.score
FROM sc a
INNER JOIN (
SELECT a.score,b.Sno,COUNT(1)
FROM sc a
INNER JOIN student b
ON a.Sno=b.Sno
GROUP BY a.score,b.Sno
HAVING COUNT(1)>1
)b
ON a.Sno=b.Sno AND a.score=b.score

43、

SELECT a.Cno
,COUNT(1) AS pnum
FROM sc a
GROUP BY 1
HAVING pnum > 5
ORDER BY pnum DESC,a.Cno 

46、

SELECT a.Sname,YEAR(CURDATE())-YEAR(a.Sage) AS '年龄'
FROM student a

47、

SELECT a.*
FROM student a
WHERE CONCAT(MONTH(a.Sage),DAY(a.Sage))>=CONCAT(MONTH(SUBDATE(CURDATE(),WEEKDAY(CURDATE()))),DAY(SUBDATE(CURDATE(),WEEKDAY(CURDATE()))))
AND CONCAT(MONTH(a.Sage),DAY(a.Sage))<=CONCAT(MONTH(SUBDATE(CURDATE(),WEEKDAY(CURDATE())-6)),DAY(SUBDATE(CURDATE(),WEEKDAY(CURDATE())-6)))

49、

SELECT a.* FROM student a WHERE MONTH(a.Sage)=MONTH(CURDATE())

50、

SELECT a.* FROM student a WHERE MONTH(a.Sage)=MONTH(CURDATE())+1