经典SQL查询题目

SQL查询题目

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SQL查询题目

 

条件：

Student(Sno,Sname,Sage,Ssex) 学生表

Course(Cno,Cname,Tno) 课程表

SC(Sno,Cno,score) 成绩表（选课表）

Teacher(Tno,Tname) 教师表

 

问题：

一、查询“001”课程比“002”课程成绩高的全部学生的学号；

  select a.sno from (select sno,score from SC where cno='001') a,(select sno,score

  from SC where cno='002') b

  where a.score>b.score and a.sno=b.sno;

 

二、查询平均成绩大于60分的同窗的学号和平均成绩；

 select SNO,avg(score)  from sc  group by SNO having avg(score) >60;

三、查询全部同窗的学号、姓名、选课数、总成绩；

 select Student.SNO,Student.Sname,count(SC.CNO),sum(score)

 from Student left Outer join SC on Student.SNO=SC.SNO

 group by Student.SNO,Sname

四、查询姓“李”的老师的个数；

 select count(distinct(Tname))

  from Teacher where Tname like '李%';

五、查询没学过“叶平”老师课的同窗的学号、姓名；

 select Student.SNO,Student.Sname  from Student 

 where SNO not in (select distinct(SC.SNO) from SC,Course,Teacher where  SC.CNO=Course.CNO and Teacher.Tno=Course.Tno and Teacher.Tname='叶平');

六、查询学过“001”而且也学过编号“002”课程的同窗的学号、姓名；

select Student.SNO,Student.Sname from Student,SC where Student.SNO=SC.SNO and SC.CNO='001'and exists( Select * from SC as SC_2 where SC_2.SNO=SC.SNO and SC_2.CNO='002');

七、查询学过“叶平”老师所教的全部课的同窗的学号、姓名；

select SNO,Sname

  from Student

  where SNO in (select SNO from SC ,Course ,Teacher where SC.CNO=Course.CNO and Teacher.TNO=Course.TNO and Teacher.Tname='叶平' group by SNO having count(SC.CNO)=(select count(CNO) from Course,Teacher  where Teacher.TNO=Course.TNO and Tname='叶平'));

八、查询课程编号“002”的成绩比课程编号“001”课程低的全部同窗的学号、姓名； 

Select SNO,Sname from (select Student.SNO,Student.Sname,score ,(select score from SC SC_2 where SC_2.SNO=Student.SNO and SC_2.CNO='002') score2

  from Student,SC where Student.SNO=SC.SNO and CNO='001') S_2 where score2 <score;

九、查询全部课程成绩小于60分的同窗的学号、姓名； 

select SNO,Sname

  from Student

  where SNO not in (select Student.SNO from Student,SC where S.SNO=SC.SNO and score>60);

十、查询没有学全全部课的同窗的学号、姓名；   

select Student.SNO,Student.Sname

    from Student,SC

    where Student.SNO=SC.SNO group by  Student.SNO,Student.Sname having count(CNO) <(select count(CNO) from Course);

 

十一、查询至少有一门课与学号为“1001”的同窗所学相同的同窗的学号和姓名；  

select SNO,Sname from Student,SC where Student.SNO=SC.SNO and CNO in select CNO from SC where SNO='1001';

十二、查询至少学过学号为“001”同窗全部一门课的其余同窗学号和姓名； 

select distinct SC.SNO,Sname

    from Student,SC

    where Student.SNO=SC.SNO and CNO in (select CNO from SC where SNO='001');

1三、把“SC”表中“叶平”老师教的课的成绩都更改成此课程的平均成绩；

update SC set score=(select avg(SC_2.score)

    from SC SC_2

    where SC_2.CNO=SC.CNO) from Course,Teacher where Course.CNO=SC.CNO and Course.TNO=Teacher.TNO and Teacher.Tname='叶平');

   
1四、查询和“1002”号的同窗学习的课程彻底相同的其余同窗学号和姓名；

select SNO from SC where CNO in (select CNO from SC where SNO='1002')

    group by SNO having count(*)=(select count(*) from SC where SNO='1002');

   
1五、删除学习“叶平”老师课的SC表记录； 

DelectSC

    from course ,Teacher 

    where Course.CNO=SC.CNO and Course.TNO= Teacher.TNO and Tname='叶平';

1六、向SC表中插入一些记录，这些记录要求符合如下条件：没有上过编号“003”课程的同窗学号、2号课的平均成绩；   

Insert SC select SNO,'002',(Select avg(score)

    from SC where CNO='002') from Student where SNO not in (Select SNO from SC where CNO='002');

1七、查询各科成绩最高和最低的分：以以下形式显示：课程ID，最高分，最低分 

SELECT SNO as 学生ID

        ,(SELECT score FROM SC WHERE SC.SNO=t.SNO AND CNO='004') AS 数据库

        ,(SELECT score FROM SC WHERE SC.SNO=t.SNO AND CNO='001') AS 企业管理

        ,(SELECT score FROM SC WHERE SC.SNO=t.SNO AND CNO='006') AS 英语

        ,COUNT(*) AS 有效课程数, AVG(t.score) AS 平均成绩

    FROM SC AS t

    GROUP BY SNO

    ORDER BY avg(t.score) 

1八、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 t.CNO AS 课程号,max(course.Cname)AS 课程名,isnull(AVG(score),0) AS 平均成绩

        ,100 * SUM(CASE WHEN  isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数

    FROM SC T,Course

    where t.CNO=course.CNO

    GROUP BY t.CNO

    ORDER BY 100 * SUM(CASE WHEN  isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC

 

1九、查询不一样老师所教不一样课程平均分从高到低显示

SELECT max(Z.TNO) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.CNO AS 课程ＩＤ,MAX(C.Cname) AS 课程名称,AVG(Score) AS 平均成绩

    FROM SC AS T,Course AS C ,Teacher AS Z

    where T.CNO=C.CNO and C.TNO=Z.TNO

  GROUP BY C.CNO

  ORDER BY AVG(Score) DESC

 

20、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60]

SELECT SC.CNO as 课程ID, Cname as 课程名称

        ,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85]

        ,SUM(CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70]

        ,SUM(CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60]

        ,SUM(CASE WHEN score < 60 THEN 1 ELSE 0 END) AS [60 -]

    FROM SC,Course

    where SC.CNO=Course.CNO

    GROUP BY SC.CNO,Cname;

 

2一、查询各科成绩前三名的记录:(不考虑成绩并列状况)   

SELECT t1.SNO as 学生ID,t1.CNO as 课程ID,Score as 分数

      FROM SC t1

      WHERE score IN (SELECT TOP 3 score

              FROM SC

              WHERE t1.CNO= CNO

            ORDER BY score DESC

              )

      ORDER BY t1.CNO;

2二、查询每门课程被选修的学生数

select cno,count(SNO) from sc group by CNO;

2三、查询出只选修了一门课程的所有学生的学号和姓名

select SC.SNO,Student.Sname,count(CNO) AS 选课数

  from SC ,Student

  where SC.SNO=Student.SNO group by SC.SNO ,Student.Sname having count(CNO)=1;

2四、查询男生、女生人数

Select count(Ssex) as 男生人数from Student group by Ssex having Ssex='男';

Select count(Ssex) as 女生人数from Student group by Ssex having Ssex='女'；

2五、查询姓“张”的学生名单 

SELECT Sname FROM Student WHERE Sname like '张%';

2六、查询同名同性学生名单，并统计同名人数

select Sname,count(*) from Student group by Sname having  count(*)>1;

2七、1981年出生的学生名单(注：Student表中Sage列的类型是datetime)  

select Sname,  CONVERT(char (11),DATEPART(year,Sage)) as age

    from student

    where  CONVERT(char(11),DATEPART(year,Sage))='1981';

2八、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 CNO,Avg(score) from SC group by CNO order by Avg(score),CNO DESC ;

2九、查询平均成绩大于85的全部学生的学号、姓名和平均成绩

select Sname,SC.SNO ,avg(score)

    from Student,SC

    where Student.SNO=SC.SNO group by SC.SNO,Sname having  avg(score)>85;

30、查询课程名称为“数据库”，且分数低于60的学生姓名和分数

Select Sname,isnull(score,0)

    from Student,SC,Course

    where SC.SNO=Student.SNO and SC.CNO=Course.CNO and  Course.Cname='数据库'and score <60;

3一、查询全部学生的选课状况；

SELECT SC.SNO,SC.CNO,Sname,Cname

    FROM SC,Student,Course

    where SC.SNO=Student.SNO and SC.CNO=Course.CNO ;

3二、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  distinct student.SNO,student.Sname,SC.CNO,SC.score

    FROM student,Sc

    WHERE SC.score>=70 AND SC.SNO=student.SNO;

3三、查询不及格的课程，并按课程号从大到小排列

select cno from sc where scor e <60 order by CNO ;

3四、查询课程编号为003且课程成绩在80分以上的学生的学号和姓名；

select SC.SNO,Student.Sname from SC,Student where SC.SNO=Student.SNO and Score>80 and CNO='003';

3五、求选了课程的学生人数

select count(*) from sc;

3六、查询选修“叶平”老师所授课程的学生中，成绩最高的学生姓名及其成绩

select Student.Sname,score

    from Student,SC,Course C,Teacher

    where Student.SNO=SC.SNO and SC.CNO=C.CNO and C.TNO=Teacher.TNO and Teacher.Tname='叶平' and SC.score=(select max(score)from SC where CNO=C.CNO );

3七、查询各个课程及相应的选修人数

select count(*) from sc group by CNO;

3八、查询不一样课程成绩相同的学生的学号、课程号、学生成绩

select distinct  A.SNO,B.score from SC A  ,SC B where A.Score=B.Score and A.CNO <>B.CNO ;

3九、查询每门功成绩最好的前两名

SELECT t1.SNO as 学生ID,t1.CNO as 课程ID,Score as 分数

      FROM SC t1

      WHERE score IN (SELECT TOP 2 score

              FROM SC

              WHERE t1.CNO= CNO  

            ORDER BY score DESC

              )

      ORDER BY t1.CNO;

40、统计每门课程的学生选修人数（超过10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，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  CNO as 课程号,count(*) as 人数

    from  sc 

    group  by  CNO

    order  by  count(*) desc,cno

4一、检索至少选修两门课程的学生学号

select  SNO 

    from  sc 

    group  by  sno

    having  count(*)  >  =  2

4二、查询所有学生都选修的课程的课程号和课程名

select  CNO,Cname 

    from  Course 

    where  CNO  in  (select  cno  from  sc group  by  cno)

4三、查询没学过“叶平”老师讲授的任一门课程的学生姓名

select Sname from Student where SNO not in (select SNO from Course,Teacher,SC where Course.TNO=Teacher.TNO and SC.CNO=course.CNO and Tname='叶平');

4四、查询两门以上不及格课程的同窗的学号及其平均成绩

select SNO,avg(isnull(score,0)) from SC where SNO in (select SNO from SC where score <60 group by SNO having count(*)>2)group by SNO;

4五、检索“004”课程分数小于60，按分数降序排列的同窗学号

select SNO from SC where CNO='004'and score <60 order by score desc;

4六、删除“002”同窗的“001”课程的成绩

delete from Sc where SNO='001'and CNO='001';