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SQL小练习

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Student(SID, Sname, Sage, Ssex) 学生表

Course(CID, Cname, TID) 课程表

SC(SID, CID, score) 成绩表

Teacher(TID, 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; 
    
    
2、查询平均成绩大于60分的同学的学号和平均成绩; 
    
    
3、查询所有同学的学号、姓名、选课数、总成绩; 
    
    
4、查询姓“李”的老师的个数; 
    
    
5、查询没学过“叶平”老师课的同学的学号、姓名; 
    
    
6、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名; 
    
    
7、查询学过“叶平”老师所教的所有课的同学的学号、姓名; 
    
    
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; 
    
    
9、查询所有课程成绩小于60分的同学的学号、姓名; 
    
    
10、查询没有学全所有课的同学的学号、姓名; 
    
    
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; 
    
    
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; 
    
    
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; 
    
    
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; 
    
    
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15、删除学习“叶平”老师课的SC表记录; 
    
    
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; 
    
    
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 
    
    
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 
    
    
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 
    
    
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) 
    
    
21、查询不同老师所教不同课程平均分从高到低显示 
    
    
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) 
    
    
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] 
    
    
24、查询学生平均成绩及其名次 
    
    
25、查询各科成绩前三名的记录:(不考虑成绩并列情况) 
      
      
26、查询每门课程被选修的学生数 
    
    
27、查询出只选修了一门课程的全部学生的学号和姓名 
    
    
28、查询男生、女生人数 
    
    
29、查询姓“张”的学生名单 
    
    
30、查询同名同性学生名单,并统计同名人数 
    
    
31、1981年出生的学生名单(注:Student表中Sage列的类型是datetime) 
    
    
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 
    
    
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 
    
    
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 
    
    
35、查询所有学生的选课情况; 
    
    
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; 
    
    
37、查询不及格的课程,并按课程号从大到小排列 
    
    
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; 
    
    
39、求选了课程的学生人数 
    
    
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 
    
    
41、查询各个课程及相应的选修人数 
    
    
42、查询不同课程成绩相同的学生的学号、课程号、学生成绩 
    
    
43、查询每门功成绩最好的前两名 
    
    
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 
    
    
45、检索至少选修两门课程的学生学号 
    
    
46、查询全部学生都选修的课程的课程号和课程名 
    
    
47、查询没学过“叶平”老师讲授的任一门课程的学生姓名 
    
    
48、查询两门以上不及格课程的同学的学号及其平均成绩 

 

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答案: 

1、查询“001”课程比“002”课程成绩高的所有学生的学号; 
    select a.SID from (select Sid,score from SC where CID='001') a,(select Sid,score 
    from SC where CID='002') b 
    where a.score>b.score and a.Sid=b.Sid; 
    
2、查询平均成绩大于60分的同学的学号和平均成绩; 
    select SID,avg(score) 
    from sc 
    group by SID having avg(score) >60; 
    
3、查询所有同学的学号、姓名、选课数、总成绩; 
    select Student.SID,Student.Sname,count(SC.CID),sum(score) 
    from Student left Outer join SC on Student.SID=SC.SID 
    group by Student.SID,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.SID,Student.Sname 
    from Student 
where SID not in (select distinct(SC.SID) from SC,Course,Teacher 
where SC.CID=Course.CID and Teacher.TID=Course.TID 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.SID,Student.Sname 
    from Student,SC 
    where Student.SID=SC.SID and SC.CID='001'and exists( 
Select * from SC as SC_2 where SC_2.SID=SC.SID and SC_2.CID='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 SID,Sname 
    from Student 
    where SID in (select SID from SC ,Course ,Teacher 
            where SC.CID=Course.CID and Teacher.TID=Course.TID and Teacher.Tname='叶平' 
            group by SID having count(SC.CID)=(select count(CID) from Course,Teacher 
where Teacher.TID=Course.TID 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 SID,Sname from (select Student.SID,Student.Sname,score ,(select score from SC SC_2 where SC_2.SID=Student.SID and SC_2.CID='002') score2 
    from Student,SC where Student.SID=SC.SID and CID='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 SID,Sname 
    from Student 
    where SID not in (select Student.SID from Student,SC where S.SID=SC.SID and score>60); 
    
10、查询没有学全所有课的同学的学号、姓名; 
    select Student.SID,Student.Sname 
    from Student,SC 
    where Student.SID=SC.SID group by Student.SID,Student.Sname having count(CID) <(select count(CID) 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 SID,Sname from Student,SC where Student.SID=SC.SID and CID in select CID from SC where SID='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.SID,Sname 
    from Student,SC 
    where Student.SID=SC.SID and CID in (select CID from SC where SID='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.CID=SC.CID )
from Course,Teacher where Course.CID=SC.CID and Course.TID=Teacher.TID 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 SID from SC where CID in (select CID from SC where SID='1002') 
    group by SID having count(*)=(select count(*) from SC where SID='1002'); 
    
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15、删除学习“叶平”老师课的SC表记录; 
    Delect SC 
    from course ,Teacher 
    where Course.CID=SC.CID and Course.TID= Teacher.TID 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 SID,'002',(Select avg(score) 
    from SC where CID='002') from Student where SID not in (Select SID from SC where CID='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 SID as 学生ID 
        ,(SELECT score FROM SC WHERE SC.SID=t.SID AND CID='004') AS 数据库 
        ,(SELECT score FROM SC WHERE SC.SID=t.SID AND CID='001') AS 企业管理 
        ,(SELECT score FROM SC WHERE SC.SID=t.SID AND CID='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 SID 
    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.CID As 课程ID,L.score AS 最高分,R.score AS 最低分 
    FROM SC L ,SC AS R 
    WHERE L.CID = R.CID and 
        L.score = (SELECT MAX(IL.score) 
                      FROM SC AS IL,Student AS IM 
                      WHERE L.CID = IL.CID and IM.SID=IL.SID 
                      GROUP BY IL.CID) 
        AND 
        R.Score = (SELECT MIN(IR.score) 
                      FROM SC AS IR 
                      WHERE R.CID = IR.CID 
                  GROUP BY IR.CID 
                    ); 
                    
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.CID 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.CID=course.CID 
    GROUP BY t.CID 
    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 CID ='001' THEN score ELSE 0 END)/SUM(CASE CID WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分 
        ,100 * SUM(CASE WHEN CID = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CID = '001' THEN 1 ELSE 0 END) AS 企业管理及格百分数 
        ,SUM(CASE WHEN CID = '002' THEN score ELSE 0 END)/SUM(CASE CID WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分 
        ,100 * SUM(CASE WHEN CID = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CID = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数 
        ,SUM(CASE WHEN CID = '003' THEN score ELSE 0 END)/SUM(CASE CID WHEN '003' THEN 1 ELSE 0 END) AS UML平均分 
        ,100 * SUM(CASE WHEN CID = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CID = '003' THEN 1 ELSE 0 END) AS UML及格百分数 
        ,SUM(CASE WHEN CID = '004' THEN score ELSE 0 END)/SUM(CASE CID WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分 
        ,100 * SUM(CASE WHEN CID = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CID = '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.TID) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.CID 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.CID=C.CID and C.TID=Z.TID 
    GROUP BY C.CID 
    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.SID 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.SID = T1.SID AND T1.CID = '001' 
            LEFT JOIN SC AS T2 
                      ON SC.SID = T2.SID AND T2.CID = '002' 
            LEFT JOIN SC AS T3 
                      ON SC.SID = T3.SID AND T3.CID = '003' 
            LEFT JOIN SC AS T4 
                      ON SC.SID = T4.SID AND T4.CID = '004' 
      WHERE student.SID=SC.SID 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.SID = T1.SID AND T1.CID = 'k1' 
            LEFT JOIN sc AS T2 
                      ON sc.SID = T2.SID AND T2.CID = 'k2' 
            LEFT JOIN sc AS T3 
                      ON sc.SID = T3.SID AND T3.CID = 'k3' 
            LEFT JOIN sc AS T4 
                      ON sc.SID = T4.SID AND T4.CID = '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.CID 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.CID=Course.CID 
    GROUP BY SC.CID,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 SID,AVG(score) AS 平均成绩 
                      FROM SC 
                  GROUP BY SID 
                  ) AS T1 
            WHERE 平均成绩> T2.平均成绩) as 名次, 
      SID as 学生学号,平均成绩 
    FROM (SELECT SID,AVG(score) 平均成绩 
            FROM SC 
        GROUP BY SID 
        ) 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.SID as 学生ID,t1.CID as 课程ID,Score as 分数 
      FROM SC t1 
      WHERE score IN (SELECT TOP 3 score 
              FROM SC 
              WHERE t1.CID= CID 
            ORDER BY score DESC 
              ) 
      ORDER BY t1.CID; 
      
26、查询每门课程被选修的学生数 
    select Cid,count(SID) from sc group by CID; 
    
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.SID,Student.Sname,count(CID) AS 选课数 
    from SC ,Student 
    where SC.SID=Student.SID group by SC.SID ,Student.Sname having count(CID)=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 CID,Avg(score) from SC group by CID order by Avg(score),CID 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.SID ,avg(score) 
    from Student,SC 
    where Student.SID=SC.SID group by SC.SID,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.SID=Student.SID and SC.CID=Course.CID and Course.Cname='数据库'and score <60; 
    
35、查询所有学生的选课情况; 
    SELECT SC.SID,SC.CID,Sname,Cname 
    FROM SC,Student,Course 
    where SC.SID=Student.SID and SC.CID=Course.CID ; 
    
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.SID,student.Sname,SC.CID,SC.score 
    FROM student,Sc 
    WHERE SC.score>=70 AND SC.SID=student.SID; 
    
37、查询不及格的课程,并按课程号从大到小排列 
    select Cid from sc where scor e <60 order by CID ; 
    
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.SID,Student.Sname from SC,Student where SC.SID=Student.SID and Score>80 and CID='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,CourseC,Teacher 
    where Student.SID=SC.SID and SC.CID=C.CID and C.TID=Teacher.TID and Teacher.Tname='叶平' and SC.score=(select max(score)from SC where CID=C.CID );
    
41、查询各个课程及相应的选修人数 
    select count(*) from sc group by CID; 
    
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.SID,B.score from SC A ,SC B where A.Score=B.Score and A.CID <>B.CID ;
    
43、查询每门功成绩最好的前两名 
    SELECT t1.SID as 学生ID,t1.CID as 课程ID,Score as 分数 
      FROM SC t1 
      WHERE score IN (SELECT TOP 2 score 
              FROM SC 
              WHERE t1.CID= CID 
            ORDER BY score DESC 
              ) 
      ORDER BY t1.CID; 
      
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 CID as 课程号,count(*) as 人数 
    from sc 
    group by CID 
    order by count(*) desc,Cid 
    
45、检索至少选修两门课程的学生学号 
    select SID 
    from sc 
    group by Sid 
    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 CID,Cname 
    from Course 
    where CID in (select Cid from sc group by Cid)
    
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 SID not in (select SID from Course,Teacher,SC where Course.TID=Teacher.TID and SC.CID=course.CID 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 SID,avg(isnull(score,0)) from SC where SID in (select SID from SC where score <60 group by SID having count(*)>2)group by SID; 

 

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