SQL面试题

Student(S#,Sname,Sage,Ssex) 学生表
Course(C#,Cname,T#) 课程表
SC(S#,C#,score) 成绩表
Teacher(T#,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.S# from ( select s#,score from SC where C# = ' 001 ' ) a,( select s#,score
  from SC where C# = ' 002 ' ) b
  where a.score > b.score and a.s# = b.s#;
2 、查询平均成绩大于60分的同学的学号和平均成绩；
    select S#, avg (score)
    from sc
    group by S# having avg (score) > 60 ;
3 、查询所有同学的学号、姓名、选课数、总成绩；
  select Student.S#,Student.Sname, count (SC.C#), sum (score)
  from Student left Outer join SC on Student.S# = SC.S#
  group by Student.S#,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.S#,Student.Sname
    from Student 
    where S# not in ( select distinct ( SC.S#) from SC,Course,Teacher where   SC.C# = Course.C# and Teacher.T# = Course.T# 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.S#,Student.Sname from Student,SC where Student.S# = SC.S# and SC.C# = ' 001 ' and exists ( Select * from SC as SC_2 where SC_2.S# = SC.S# and SC_2.C# = ' 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 S#,Sname
  from Student
  where S# in ( select S# from SC ,Course ,Teacher where SC.C# = Course.C# and Teacher.T# = Course.T# and Teacher.Tname = ' 叶平 ' group by S# having count (SC.C#) = ( select count (C#) from Course,Teacher  where Teacher.T# = Course.T# 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 S#,Sname from ( select Student.S#,Student.Sname,score ,( select score from SC SC_2 where SC_2.S# = Student.S# and SC_2.C# = ' 002 ' ) score2
  from Student,SC where Student.S# = SC.S# and C# = ' 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 S#,Sname
  from Student
  where S# not in ( select Student.S# from Student,SC where S.S# = SC.S# and score > 60 );
10 、查询没有学全所有课的同学的学号、姓名；
    select Student.S#,Student.Sname
    from Student,SC
    where Student.S# = SC.S# group by   Student.S#,Student.Sname having count (C#) < ( select count (C#) 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 S#,Sname from Student,SC where Student.S# = SC.S# and C# in select C# from SC where S# = ' 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.S#,Sname
    from Student,SC
    where Student.S# = SC.S# and C# in ( select C# from SC where S# = ' 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.C# = SC.C# ) from Course,Teacher where Course.C# = SC.C# and Course.T# = Teacher.T# 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 S# from SC where C# in ( select C# from SC where S# = ' 1002 ' )
    group by S# having count ( * ) = ( select count ( * ) from SC where S# = ' 1002 ' );
15 、删除学习“叶平”老师课的SC表记录；
    Delect SC
    from course ,Teacher 
    where Course.C# = SC.C# and Course.T# = Teacher.T# 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 S#, ' 002 ' ,( Select avg (score)
    from SC where C# = ' 002 ' ) from Student where S# not in ( Select S# from SC where C# = ' 002 ' );
17 、按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩，按如下形式显示： 学生ID,,数据库,企业管理,英语,有效课程数,有效平均分
    SELECT S# as 学生ID
        ,( SELECT score FROM SC WHERE SC.S# = t.S# AND C# = ' 004 ' ) AS 数据库
        ,( SELECT score FROM SC WHERE SC.S# = t.S# AND C# = ' 001 ' ) AS 企业管理
        ,( SELECT score FROM SC WHERE SC.S# = t.S# AND C# = ' 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 S#
    ORDER BY avg (t.score) 
18 、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 L.C# As 课程ID,L.score AS 最高分,R.score AS 最低分
    FROM SC L ,SC AS R
    WHERE L.C# = R.C# and
        L.score = ( SELECT MAX (IL.score)
                      FROM SC AS IL,Student AS IM
                      WHERE L.C# = IL.C# and IM.S# = IL.S#
                      GROUP BY IL.C#)
        AND
        R.Score = ( SELECT MIN (IR.score)
                      FROM SC AS IR
                      WHERE R.C# = IR.C#
                  GROUP BY IR.C#
                    );
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 t.C# 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.C# = course.C#
    GROUP BY t.C#
    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百分数(用"1行"显示): 企业管理（ 001 ），马克思（ 002 ），OO & UML （ 003 ），数据库（ 004 ）
    SELECT SUM ( CASE WHEN C# = ' 001 ' THEN score ELSE 0 END ) / SUM ( CASE C# WHEN ' 001 ' THEN 1 ELSE 0 END ) AS 企业管理平均分
        , 100 * SUM ( CASE WHEN C# = ' 001 ' AND score >= 60 THEN 1 ELSE 0 END ) / SUM ( CASE WHEN C# = ' 001 ' THEN 1 ELSE 0 END ) AS 企业管理及格百分数
        , SUM ( CASE WHEN C# = ' 002 ' THEN score ELSE 0 END ) / SUM ( CASE C# WHEN ' 002 ' THEN 1 ELSE 0 END ) AS 马克思平均分
        , 100 * SUM ( CASE WHEN C# = ' 002 ' AND score >= 60 THEN 1 ELSE 0 END ) / SUM ( CASE WHEN C# = ' 002 ' THEN 1 ELSE 0 END ) AS 马克思及格百分数
        , SUM ( CASE WHEN C# = ' 003 ' THEN score ELSE 0 END ) / SUM ( CASE C# WHEN ' 003 ' THEN 1 ELSE 0 END ) AS UML平均分
        , 100 * SUM ( CASE WHEN C# = ' 003 ' AND score >= 60 THEN 1 ELSE 0 END ) / SUM ( CASE WHEN C# = ' 003 ' THEN 1 ELSE 0 END ) AS UML及格百分数
        , SUM ( CASE WHEN C# = ' 004 ' THEN score ELSE 0 END ) / SUM ( CASE C# WHEN ' 004 ' THEN 1 ELSE 0 END ) AS 数据库平均分
        , 100 * SUM ( CASE WHEN C# = ' 004 ' AND score >= 60 THEN 1 ELSE 0 END ) / SUM ( CASE WHEN C# = ' 004 ' THEN 1 ELSE 0 END ) AS 数据库及格百分数
  FROM SC
21 、查询不同老师所教不同课程平均分从高到低显示
  SELECT max (Z.T#) AS 教师ID, MAX (Z.Tname) AS 教师姓名,C.C# 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.C# = C.C# and C.T# = Z.T#
  GROUP BY C.C#
  ORDER BY AVG (Score) DESC
22 、查询如下课程成绩第 3 名到第 6 名的学生成绩单：企业管理（ 001 ），马克思（ 002 ），UML （ 003 ），数据库（ 004 ）
    [ 学生ID ] , [ 学生姓名 ] ,企业管理,马克思,UML,数据库,平均成绩
    SELECT   DISTINCT top 3
      SC.S# As 学生学号,
        Student.Sname AS 学生姓名 ,
      T1.score AS 企业管理,
      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.S# = T1.S# AND T1.C# = ' 001 '
            LEFT JOIN SC AS T2
                      ON SC.S# = T2.S# AND T2.C# = ' 002 '
            LEFT JOIN SC AS T3
                      ON SC.S# = T3.S# AND T3.C# = ' 003 '
            LEFT JOIN SC AS T4
                      ON SC.S# = T4.S# AND T4.C# = ' 004 '
      WHERE student.S# = SC.S# 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.S# = T1.S# AND T1.C# = ' k1 '
            LEFT JOIN sc AS T2
                      ON sc.S# = T2.S# AND T2.C# = ' k2 '
            LEFT JOIN sc AS T3
                      ON sc.S# = T3.S# AND T3.C# = ' k3 '
            LEFT JOIN sc AS T4
                      ON sc.S# = T4.S# AND T4.C# = ' k4 '
      ORDER BY ISNULL (T1.score, 0 ) + ISNULL (T2.score, 0 ) + ISNULL (T3.score, 0 ) + ISNULL (T4.score, 0 ) DESC );

23 、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.C# 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.C# = Course.C#
    GROUP BY SC.C#,Cname;

24 、查询学生平均成绩及其名次
      SELECT 1 + ( SELECT COUNT ( distinct 平均成绩)
              FROM ( SELECT S#, AVG (score) AS 平均成绩
                      FROM SC
                  GROUP BY S#
                  ) AS T1
            WHERE 平均成绩 > T2.平均成绩) as 名次,
      S# as 学生学号,平均成绩
    FROM ( SELECT S#, AVG (score) 平均成绩
            FROM SC
        GROUP BY S#
        ) AS T2
    ORDER BY 平均成绩 desc ;
 
25 、查询各科成绩前三名的记录:(不考虑成绩并列情况)
      SELECT t1.S# as 学生ID,t1.C# as 课程ID,Score as 分数
      FROM SC t1
      WHERE score IN ( SELECT TOP 3 score
              FROM SC
              WHERE t1.C# = C#
            ORDER BY score DESC
              )
      ORDER BY t1.C#;
26 、查询每门课程被选修的学生数
  select c#, count (S#) from sc group by C#;
27 、查询出只选修了一门课程的全部学生的学号和姓名
  select SC.S#,Student.Sname, count (C#) AS 选课数
  from SC ,Student
  where SC.S# = Student.S# group by SC.S# ,Student.Sname having count (C#) = 1 ;
28 、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 ' ；
29 、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，并统计同名人数
  select Sname, count ( * ) from Student group by Sname having   count ( * ) > 1 ;;
31 、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 ' ;
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 C#, Avg (score) from SC group by C# order by Avg (score),C# DESC ;
33 、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.S# , avg (score)
    from Student,SC
    where Student.S# = SC.S# group by SC.S#,Sname having     avg (score) > 85 ;
34 、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.S# = Student.S# and SC.C# = Course.C# and   Course.Cname = ' 数据库 ' and score < 60 ;
35 、查询所有学生的选课情况；
    SELECT SC.S#,SC.C#,Sname,Cname
    FROM SC,Student,Course
    where SC.S# = Student.S# and SC.C# = Course.C# ;
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；
    SELECT   distinct student.S#,student.Sname,SC.C#,SC.score
    FROM student,Sc
    WHERE SC.score >= 70 AND SC.S# = student.S#;
37 、查询不及格的课程，并按课程号从大到小排列
    select c# from sc where scor e < 60 order by C# ;
38 、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.S#,Student.Sname from SC,Student where SC.S# = Student.S# and Score > 80 and C# = ' 003 ' ;
39 、求选了课程的学生人数
    select count ( * ) from sc;
40 、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.S# = SC.S# and SC.C# = C.C# and C.T# = Teacher.T# and Teacher.Tname = ' 叶平 ' and SC.score = ( select max (score) from SC where C# = C.C# );
41 、查询各个课程及相应的选修人数
    select count ( * ) from sc group by C#;
42 、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.S#,B.score from SC A  ,SC B where A.Score = B.Score and A.C# <> B.C# ;
43 、查询每门功成绩最好的前两名
    SELECT t1.S# as 学生ID,t1.C# as 课程ID,Score as 分数
      FROM SC t1
      WHERE score IN ( SELECT TOP 2 score
              FROM SC
              WHERE t1.C# = C#
            ORDER BY score DESC
              )
      ORDER BY t1.C#;
44 、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   C# as 课程号, count ( * ) as 人数
    from   sc 
    group   by   C#
    order   by   count ( * ) desc ,c# 
45 、检索至少选修两门课程的学生学号
    select   S# 
    from   sc 
    group   by   s#
    having   count ( * )  >   =   2
46 、查询全部学生都选修的课程的课程号和课程名
    select   C#,Cname 
    from   Course 
    where   C#  in   ( select   c#  from   sc group   by   c#) 
47 、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 S# not in ( select S# from Course,Teacher,SC where Course.T# = Teacher.T# and SC.C# = course.C# and Tname = ' 叶平 ' );
48 、查询两门以上不及格课程的同学的学号及其平均成绩
    select S#, avg ( isnull (score, 0 )) from SC where S# in ( select S# from SC where score < 60 group by S# having count ( * ) > 2 ) group by S#;
49 、检索“ 004 ”课程分数小于60，按分数降序排列的同学学号
    select S# from SC where C# = ' 004 ' and score < 60 order by score desc ;
50 、删除“ 002 ”同学的“ 001 ”课程的成绩
delete from Sc where S# = ' 001 ' and C# = ' 001 ' ;