数据库SQL基本功练习

表架构

建表语句 

测试数据

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 S.S# from Student AS S,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 distinct S#,Sname from Student,SC where Student.S#=SC.S# and SC.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# 
                    ); 

自己写的:select c# ,max(score)as 最高分 ,min(score) as 最低分 from dbo.sc  group by 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'; 

      本文转自arac 51CTO博客，原文链接：http://blog.51cto.com/skyarac/1845377，如需转载请自行联系原作者