sql面试题1

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），JAVA（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 JAVA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 JAVA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），JAVA（002），UML （003），数据库（004）  
    [学生ID],[学生姓名],企业管理,JAVA,UML,数据库,平均成绩  
    SELECT DISTINCT top 3  
    C.S# As 学生学号,  
    Student.Sname AS 学生姓名 ,  
    T1.score AS 企业管理,  
    T2.score AS JAVA,  
    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';