sql 经典面试题及答案(选课表)

SQL数据库面试题以及答案

Student(Sno,Sname,Sage,Ssex)
学生表       Sno:学号;Sname:学生姓名;Sage:学生年龄;Ssex:学生性别
Course(Cno,Cname,Tno)
课程表                    Cno,课程编号;Cname:课程名字;Tno:教授编号
SC(Sno,Cno,score)
成绩表                             Sno:学号;Cno,课程编号;score:战表
Teacher(Tno,Tname) 助教表                        Tno:教授编号;
Tname:助教名字

 

创办数据表:

create table Student(

Sno varchar(10) not null primary key,

Sname varchar(20) null,

Sage int null,

Ssex varchar(2) null

)

create table Course(

Cno varchar(10) not null primary key,

Cname varchar(20) null,

Tno varchar(20) null

)

create table SC(

Sno varchar(10) not null primary key,

Cno varchar(10) not null primary key,

score int null

)

create table Teacher(

Tno varchar(20) primary key not null,

Tname varchar(20) null

)

问题:
一、查询“00一”课程比“00二”课程战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;
2、查询平均成绩超乎57分的同桌的学号和平均成绩;
    select Sno,avg(score)
    from sc
    group by Sno having avg(score) >60;
3、查询全体同学的学号、姓名、选课数、总战表;
  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
肆、查询姓“李”的教员的个数;
  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’);
6、查询学过“00一”并且也学过数码“002”课程的同校的学号、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”老师所教的全体课的同班的学号、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“00贰”的成绩比课程编号“00一”课程低的持有同学的学号、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、查询全部课程成绩小于56分的同校的学号、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、查询未有学全全部课的同班的学号、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);

1一、查询至少有一门课与学号为“1001”的同室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′;
1二、查询至少学过学号为“00壹”同学全部壹门课的别的同学学号和人名;
    select distinct SC.Sno,Sname
    from Student,SC
    where Student.Sno=SC.Sno and Cno in (select Cno from SC where
Sno=’001′);
一3、把“SC”表中“叶平”老师教的课的大圣Diego转移为此课程的平分成绩;
    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’);
1肆、查询和“拾0二”号的同学学习的课程完全相同的别的同学学号和人名;
    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′);
一五、删除学习“叶平”老师课的SC表记录;
    Delect SC
    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,那些记录需求符合以下原则:未有上过编号“003”课程的校友学号、2、
    号课的平均战绩;
    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、按平均战表从高到低突显全数学员的“数据库”、“企管”、“西班牙语”三门的课程战表,按如下格局显示:
学生ID,,数据库,企管,土耳其语,有效课程数,有效平均分
    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=’00一’) AS
企管
        ,(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、查询各科成绩最高和最低的分:以如下方式显得:课程ID,最高分,最低分
    SELECT L.Cno As 课程ID,L.score AS 最高分,R.score AS 最低分
    FROM SC L ,SC AS R
    WHERE L.Cno = R.Cno and
        L.score = (SELECT MAX(IL.score)
                      FROM SC AS IL,Student AS IM
                      WHERE L.Cno = IL.Cno and IM.Sno=IL.Sno
                      GROUP BY IL.Cno)
        AND
        R.Score = (SELECT MIN(IR.score)
                      FROM SC AS IR
                      WHERE R.Cno = IR.Cno
                  GROUP BY IR.Cno
                    );
1玖、按各科平均战表从低到高和及格率的百分比从高到低依次
    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
20、查询如下课程平均成绩和及格率的比例(用”1行”显示):
企管(001),马克思(002),OO&UML (00三),数据库(00四)
    SELECT SUM(CASE WHEN Cno =’00壹’ THEN score ELSE 0 END)/SUM(CASE Cno
WHEN ’00一’ THEN 一 ELSE 0 END) AS 企管平均分
        ,100 * SUM(CASE WHEN Cno = ‘001’ AND score >= 60 THEN 一 ELSE
0 END)/SUM(CASE WHEN Cno = ’00一’ THEN 1 ELSE 0 END) AS
企管及格百分数
        ,SUM(CASE WHEN Cno = ’00贰’ THEN score ELSE 0 END)/SUM(CASE Cno
WHEN ’00二’ THEN 一 ELSE 0 END) AS 马克思平均分
        ,100 * SUM(CASE WHEN Cno = ’00二’ AND score >= 60 THEN 1 ELSE
0 END)/SUM(CASE WHEN Cno = ’00贰’ THEN 一 ELSE 0 END) AS
马克思及格百分数
        ,SUM(CASE WHEN Cno = ‘003’ THEN score ELSE 0 END)/SUM(CASE Cno
WHEN ‘003’ THEN 1 ELSE 0 END) AS UML平均分
        ,100 * SUM(CASE WHEN Cno = ’00三’ AND score >= 60 THEN 一 ELSE
0 END)/SUM(CASE WHEN Cno = ’00三’ THEN 一 ELSE 0 END) AS UML及格百分数
        ,SUM(CASE WHEN Cno = ‘004’ THEN score ELSE 0 END)/SUM(CASE Cno
WHEN ’00四’ THEN 一 ELSE 0 END) AS 数据库平均分
        ,100 * SUM(CASE WHEN Cno = ’00肆’ AND score >= 60 THEN 壹 ELSE
0 END)/SUM(CASE WHEN Cno = ’00四’ THEN 壹 ELSE 0 END) AS
数据库及格百分数
  FROM SC
2一、查询分化老师所教差别科目平均分从高到低展现
  SELECT max(Z.Tno) AS 教授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
2二、查询如下课程战表第 三 名到第 陆名的学习者战绩单:企管(00壹),马克思(00二),UML
(003),数据库(004)
    [学生ID],[学员姓名],企业管理,马克思,UML,数据库,平均成绩
    SELECT  DISTINCT top 3
      SC.Sno As 学生学号,
        Student.Sname AS 学生姓名 ,
      T1.score AS 企管,
      T2.score AS 马克思,
      T3.score AS UML,
      T4.score AS 数据库,
      ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) +
ISNULL(T4.score,0) as 总分
      FROM Student,SC  LEFT JOIN SC AS T1
                      ON SC.Sno = T1.Sno AND T1.Cno = ‘001’
            LEFT JOIN SC AS T2
                      ON SC.Sno = T2.Sno AND T2.Cno = ‘002’
            LEFT JOIN SC AS T3
                      ON SC.Sno = T3.Sno AND T3.Cno = ‘003’
            LEFT JOIN SC AS T4
                      ON SC.Sno = T4.Sno AND T4.Cno = ‘004’
      WHERE student.Sno=SC.Sno and
      ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) +
ISNULL(T4.score,0)
      NOT IN
      (SELECT
            DISTINCT
            TOP 15 WITH TIES
            ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0)

  • ISNULL(T4.score,0)
          FROM sc
                LEFT JOIN sc AS T1
                          ON sc.Sno = T1.Sno AND T1.Cno = ‘k1’
                LEFT JOIN sc AS T2
                          ON sc.Sno = T2.Sno AND T2.Cno = ‘k2’
                LEFT JOIN sc AS T3
                          ON sc.Sno = T3.Sno AND T3.Cno = ‘k3’
                LEFT JOIN sc AS T4
                          ON sc.Sno = T4.Sno AND T4.Cno = ‘k4’
          ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) +
    ISNULL(T3.score,0) + ISNULL(T4.score,0) DESC);

贰三、总括列印各科成绩,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;

二4、查询学一生均成绩及其排行
      SELECT 一+(SELECT COUNT( distinct 平均成绩)
              FROM (SELECT Sno,AVG(score) AS 平均成绩
                      FROM SC
                  GROUP BY Sno
                  ) AS T1
            WHERE 平均战绩 > T二.平均成绩) as 排名,
      Sno as 学生学号,平均成绩
    FROM (SELECT Sno,AVG(score) 平均成绩
            FROM SC
        GROUP BY Sno
        ) AS T2
    O本田UR-VDEGL450 BY 平均战绩 desc;
 
贰⑤、查询各科战表前三名的笔录:(不挂念战表并列境况)
      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;
二六、查询每门学科被选修的上学的儿童数
  select Cno,count(Sno) from sc group by Cno;
27、查询出只选修了壹门学科的百分百学员的学号和姓名
  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;
2八、查询男人、女人人数
    Select count(Ssex) as 男子人数 from Student group by Ssex having
Ssex=’男’;
    Select count(Ssex) as 女人人数 from Student group by Ssex having
Ssex=’女’;
2玖、查询姓“张”的学生名单
    SELECT Sname FROM Student WHERE Sname like ‘张%’;
30、查询同名同性学生名单,并总括同有名的人数
  select Sname,count(*) from Student group by Sname
having  count(*)>1;;
3壹、1九82年降生的学生名单(注:Student表中Sage列的档次是datetime)
    select Sname,  CONVERT(char (11),DATEPART(year,Sage)) as age
    from student
    where  CONVERT(char(11),DATEPART(year,Sage))=’1981′;
32、查询每门学科的平分战绩,结果按平均成绩升序排列,平均成绩同样时,按学科号降序排列
    Select Cno,Avg(score) from SC group by Cno order by Avg(score),Cno
DESC ;
33、查询平均战绩超乎85的兼具学生的学号、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;
3四、查询课程名叫“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;
3伍、查询全部学员的选课意况;
    SELECT SC.Sno,SC.Cno,Sname,Cname
    FROM SC,Student,Course
    where SC.Sno=Student.Sno and SC.Cno=Course.Cno ;
3陆、查询其余①门科目战绩在66分以上的人名、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;
三7、查询比不上格的课程,并按学科号从大到小排列
    select Cno from sc where scor e <60 order by Cno ;
3八、查询课程编号为00三且课程成绩在七贰拾壹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′;
3玖、求选了课程的学习者人数
    select count(*) from sc;
40、查询选修“叶平”老师所授课程的学习者中,成绩最高的学习者姓名及其成绩
    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 );
肆1、查询各种学科及相应的选修人数
    select count(*) from sc group by Cno;
4二、查询分裂学科战表同样的上学的小孩子的学号、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 ;
四3、查询每门功成绩最佳的前两名
    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;
44、总括每门课程的上学的小孩子选修人数(超过十人的教程才总计)。供给输出课程号和选修人数,查询结果按人口降序排列,查询结果按人口降序排列,若人数相同,按学科号升序排列 
    select  Cno as 课程号,count(*) as 人数
    from  sc 
    group  by  Cno
    order  by  count(*) desc,Cno 
45、检索至少选修两门课程的学习者学号
    select  Sno 
    from  sc 
    group  by  Sno
    having  count(*)  >  =  2
四6、查询任何上学的小孩子都选修的课程的课程号和学科名
    select  Cno,Cname 
    from  Course 
    where  Cno  in  (select  Cno  from  sc group  by  Cno) 
四柒、查询没学过“叶平”老师教师的任1门科目标上学的小孩子姓名
    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’);
4八、查询两门以上比不上格课程的同室的学号及其平均战表
    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;
4九、检索“00肆”课程分数小于60,按分数降序排列的校友学号
    select Sno from SC where Cno=’004’and score <60 order by score
desc;

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