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  • 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:


    1、查询“001”课程比“002”课程成绩高的所有学生的学号;

      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;

    2、查询平均成绩大于60分的同学的学号和平均成绩;

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


    3、查询所有同学的学号、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


    4、查询姓“李”的老师的个数;

     select count(distinct(Tname))

      from Teacher where Tname like '李%';


    5、查询没学过“叶平”老师课的同学的学号、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');


    6、查询学过“001”并且也学过编号“002”课程的同学的学号、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');


    7、查询学过“叶平”老师所教的所有课的同学的学号、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'));


    8、查询课程编号“002”的成绩比课程编号“001”课程低的所有同学的学号、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;


    9、查询所有课程成绩小于60分的同学的学号、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);


    10、查询没有学全所有课的同学的学号、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);

    11、查询至少有一门课与学号为“1001”的同学所学相同的同学的学号和姓名;  

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


    12、查询至少学过学号为“001”同学所有一门课的其他同学学号和姓名; 

    select distinct SC.SNO,Sname

        from Student,SC

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


    13、把“SC”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩;

    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');

       
    14、查询和“1002”号的同学学习的课程完全相同的其他同学学号和姓名;

    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');

       
    15、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';


    16、向SC表中插入一些记录,这些记录要求符合以下条件:没有上过编号“003”课程的同学学号、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');


    17、查询各科成绩最高和最低的分:以如下形式显示: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) 


    18、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

    19、查询不同老师所教不同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;

    21、查询各科成绩前三名的记录:(不考虑成绩并列情况)   

    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;


    22、查询每门课程被选修的学生数

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


    23、查询出只选修了一门课程的全部学生的学号和姓名

    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;


    24、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';


    25、查询姓“张”的学生名单 

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


    26、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;


    27、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';


    28、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 ;


    29、查询平均成绩大于85的所有学生的学号、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;


    31、查询所有学生的选课情况;

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

        FROM SC,Student,Course

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


    32、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;


    33、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 ;


    34、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';


    35、求选了课程的学生人数

    select count(*) from sc;


    36、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 );


    37、查询各个课程及相应的选修人数

    select count(*) from sc group by CNO;


    38、查询不同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 ;


    39、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


    41、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


    42、查询全部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)


    43、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');


    44、查询两门以上不及格课程的同学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;


    45、检索“004”课程分数小于60,按分数降序排列的同学学号

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


    46、删除“002”同学的“001”课程的成绩

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

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  • 原文地址:https://www.cnblogs.com/misswjr/p/9682116.html
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