有关学生表，选课表和课程表的sql语句

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

create table Student(S# varchar(20),Sname varchar(10),Sage int,Ssex varchar(2))

前面加一列序号：

if

exists(select table_name from information_schema.tables

where table_name='Temp_Table')

drop table Temp_Table

go

select 排名=identity(int,1,1),* INTO   Temp_Table    from Student

go

select * from Temp_Table

go

drop database [ ]  --删除空的没有名字的数据库

问题：

1、查询“”课程比“”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“”并且也学过编号“”课程的同学的学号、姓名；

select Student.S#,Student.Sname from Student,SCwhere 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“”的成绩比课程编号“”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_2where SC_2.S#=Student.S# and SC_2.C#='002')score2

from Student,SCwhere Student.S#=SC.S# and C#='001')S_2 where score2 <score;

9、查询所有课程成绩小于分的同学的学号、姓名；

select S#,Sname

from Student

where S# not in (select Student.S# from Student,SCwhere 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“”的同学所学相同的同学的学号和姓名；

  select S#,Snamefrom Student,SCwhere Student.S#=SC.S# and C# in select C# from SC where S#='1001'; 

12、查询至少学过学号为“”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“”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“”课程的同学学号、、

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（），马克思（），OO&UML （），数据库（）

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 SCAS 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名到第名的学生成绩单：企业管理（），马克思（），UML （），数据库（）

[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 SCt1 

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 scgroup 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、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 scwhere scor e <60 order by C# ; 

38、查询课程编号为且课程成绩在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,CourseC,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 scgroup 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 SCt1 

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“”课程分数小于，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“”同学的“”课程的成绩

delete from Sc where S#='001'and C#='001';