sql查询语句练习实验一

建立四张表：

C1_Student(Sno,Sname,Sage,Ssex) 学生表
C2_Course(Cno,Cname,Tno) 课程表
C3_SC(Sno,Cno,score) 成绩表
C4_Teacher(Tno,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 distinct a.Sno from(select Sno,Grade from C3_SC where Cno='0000000000')a,(select Sno,Grade from C3_SC where Cno='0000000001')b

where a.Grade>b.Grade;

2、查询平均成绩大于60分的同学的学号和平均成绩；
       select Sno,AVG(Grade)

from C3_SC

group by Sno

having AVG(Grade)>60;

3、查询所有同学的学号、姓名、选课数、总成绩；
       select C1_Student.Sno,Sname,COUNT(C3_SC.Cno),SUM(Grade)

from C1_Student left Outer join C3_SC on C1_Student.Sno=C3_SC.Sno

group by C1_Student.Sno,Sname;

4、查询姓“李”的老师的个数；
       select COUNT(distinct(Tname))

from C4_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 Sno,Sname

from C1_Student

where Sno not in(select distinct(Sno) from C3_SC,C2_Course,C4_Teacher where C4_Teacher.Tname='范平'and C4_Teacher.Tno=C2_Course.Tno and C2_Course.Cno = C3_SC.Cno)

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 Sno,Sname

from C1_Student

where Sno in(select Sno from C3_SC where C3_SC.Cno='0000000000')and Sno in(select Sno from C3_SC where C3_SC.Cno='0000000001');

7、查询学过“叶平”老师所教的所有课的同学的学号、姓名；
       select Sno,Sname

from C1_Student

where Sno in (select Sno from C3_SC ,C2_Course ,C4_Teacher where C3_SC.Cno=C2_Course.Cno and C4_Teacher.Tno=C2_Course.Tno and   C4_Teacher.Tname='陈博' group by Sno having count(C3_SC.Cno)=(select count(Cno) from C2_Course,C4_Teacher  where     C4_Teacher.Tno=C2_Course.Tno and   Tname='陈博'));

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 Sno,Sname

from(select C1_Student.Sno,C1_Student.Sname,Grade,(select Grade from C3_SC C3_SC_2 where C3_SC_2.Sno=C1_Student.Sno and     C3_SC_2.Cno='0000000001')Grade2 from C1_Student,C3_SC where C1_Student.Sno=C3_SC.Sno and Cno='0000000000')Grade where Grade2<Grade;

9、查询所有课程成绩小于60分的同学的学号、姓名；
        select Sno,Sname

from C1_Student where Sno in (select Sno from C3_SC where     C3_SC.Grade<60);

10、查询没有学全所有课的同学的学号、姓名；
       select C1_Student.Sno,C1_Student.Sname

from C1_Student,C3_SC where C1_Student.Sno=C3_SC.Sno group by   C1_Student.Sno,C1_Student.Sname having COUNT(Cno)<(select   COUNT(C2_Course.Cno) from C2_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 C1_Student.Sno,C1_Student.Sname

from C1_Student,C3_SC where C1_Student.Sno=C3_SC.Sno and C3_SC.Cno in (select Cno from C3_SC where Sno='0000003') and    C1_Student.Sno !='0000003';

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 C1_Student.Sno,C1_Student.Sname

from C1_Student,C3_SC where C1_Student.Sno=C3_SC.Sno and C3_SC.Cno in (select Cno from C3_SC where Sno='0000003') and    C1_Student.Sno !='0000003';

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 C3_SC set Grade=(select AVG(C3_SC_2.Grade) from C3_SC C3_SC_2 where C3_SC.Cno=C3_SC_2.Cno)

from C2_Course,C4_Teacher where C2_Course.Cno=C3_SC.Cno and    C2_Course.Tno=C4_Teacher.Tno and C4_Teacher.Tname='范平';

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；
         use 学生数据库

select Sno,Sname from C1_Student where Sno in(

select Sno from C3_SC where Cno in (select Cno from C3_SC where   Sno='0000000') group by

Sno having count(*)=(select count(*) from C3_SC where     Sno='0000000'));

15、删除学习“叶平”老师课的SC表记录；
         Delete C3_SC

from C2_course,C4_Teacher

where C2_Course.Cno=C3_SC.Cno and C2_Course.Tno= C4_Teacher.Tno

and Tname='范平';

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 C3_SC select Sno,'0000000000',(Select avg(Grade)

from C3_SC where Cno='0000000000') from C1_Student where Sno not in (Select Sno from C3_SC where     Cno='0000000000');
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 Sno as 学生ID

,(SELECT Grade FROM C3_SC WHERE C3_SC.Sno=t.Sno AND     Cno='0000000000') AS C语言

,(SELECT Grade FROM C3_SC WHERE C3_SC.Sno=t.Sno AND Cno='0000000002')    AS 高等数学

,COUNT(*) AS 有效课程数, AVG(t.Grade) AS 平均成绩

FROM C3_SC AS t

GROUP BY Sno

ORDER BY avg(t.Grade) 
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 distinct L.Cno As 课程ID,L.Grade AS 最高分,R.Grade AS 最低分

FROM C3_SC L ,C3_SC R

WHERE L.Cno = R.Cno and

L.Grade = (SELECT MAX(IL.Grade)

FROM C3_SC AS IL,C1_Student AS IM

WHERE L.Cno = IL.Cno and IM.Sno=IL.Sno

GROUP BY IL.Cno)

AND

R.Grade = (SELECT MIN(IR.Grade)

FROM C3_SC AS IR

WHERE R.Cno = IR.Cno

GROUP BY                                                      IR.Cno);

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.Cno AS 课程号,max(C2_Course.Cname)AS 课程    名,isnull(AVG(Grade),0) AS 平均成绩

,100 * SUM(CASE WHEN  isnull(Grade,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数

FROM C3_SC T,C2_Course

where t.Cno=C2_Course.Cno

GROUP BY t.Cno

ORDER BY 100 * SUM(CASE WHEN  isnull(Grade,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 Cno ='0000000000' THEN Grade ELSE 0 END)/SUM(CASE   Cno WHEN '0000000000' THEN 1 ELSE 0 END) AS C语言平均分

,100 * SUM(CASE WHEN Cno = '0000000000' AND Grade >= 60 THEN 1 ELSE    0 END)/SUM(CASE WHEN Cno = '0000000000' THEN 1 ELSE 0 END

) AS C语言及格百分数

,SUM(CASE WHEN Cno = '0000000002' THEN Grade ELSE 0 END)/SUM(CASE Cno WHEN '0000000002' THEN 1 ELSE 0 END) AS 高等数学平均分

,100 * SUM(CASE WHEN Cno = '0000000002' AND Grade >= 60 THEN 1 ELSE    0 END)/SUM(CASE WHEN Cno = '0000000002' THEN 1 ELSE 0 END) AS 高等   数学及格百分数

FROM C3_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.Tno) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.Cno AS 课程Ｉ Ｄ,MAX(C.Cname) AS 课程名称,AVG(Grade) AS 平均成绩

FROM C3_SC AS T,C2_Course AS C ,C4_Teacher AS Z

where T.Cno=C.Cno and C.Tno=Z.Tno

GROUP BY C.Cno

ORDER BY AVG(Grade) 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

C3_SC.Sno As 学生学号,

C1_Student.Sname AS 学生姓名 ,

T1.Grade AS C语言,

T2.Grade AS 数据库,

T3.Grade AS 高等数学,

ISNULL(T1.Grade,0) + ISNULL(T2.Grade,0) + ISNULL(T3.Grade,0) as 总分

FROM C1_Student,C3_SC  LEFT JOIN C3_SC AS T1

ON C3_SC.Sno = T1.Sno AND T1.Cno = '0000000000'

LEFT JOIN C3_SC AS T2

ON C3_SC.Sno = T2.Sno AND T2.Cno = '0000000001'

LEFT JOIN C3_SC AS T3

ON C3_SC.Sno =T3.Sno AND T3.Cno = '0000000002'

WHERE C1_Student.Sno=C3_SC.Sno and

ISNULL(T1.Grade,0) + ISNULL(T2.Grade,0) + ISNULL(T3.Grade,0)

NOT IN

(SELECT

DISTINCT

TOP 15 WITH TIES

ISNULL(T1.Grade,0) + ISNULL(T2.Grade,0) + ISNULL(T3.Grade,0)

FROM C3_SC

LEFT JOIN C3_SC AS T1

ON C3_SC.Sno = T1.Sno AND T1.Cno= 'K1'

LEFT JOIN C3_SC AS T2

ON C3_SC.Sno = T2.Sno AND T2.Cno = 'K2'

LEFT JOIN C3_SC AS T3

ON C3_SC.Sno = T3.Sno AND T3.Cno = 'K3'

ORDER BY ISNULL(T1.Grade,0) + ISNULL(T2.Grade,0) + ISNULL(T3.Grade,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 C3_SC.Cno as 课程ID, Cname

as 课程名称

,SUM(CASE WHEN Grade BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85]

,SUM(CASE WHEN Grade BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70]

,SUM(CASE WHEN Grade BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60]

,SUM(CASE WHEN Grade < 60 THEN 1 ELSE 0 END) AS [60 -]

FROM C3_SC,C2_Course where C3_SC.Cno=C2_Course.Cno

GROUP BY C3_SC.Cno,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 Sno,AVG(Grade) AS 平均成绩

FROM C3_SC

GROUP BY Sno

) AS T1

WHERE 平均成绩 > T2.平均成绩) as 名次,

Sno as 学生学号,平均成绩

FROM (SELECT Sno,AVG(Grade) 平均成绩

FROM C3_SC

GROUP BY Sno

) 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.Sno as 学生ID,t1.Cno as 课程ID,Grade as 分数

FROM C3_SC t1

WHERE Grade IN (SELECT TOP 3 Grade

FROM C3_SC

WHERE t1.Cno= Cno

ORDER BY Grade DESC

)

ORDER BY t1.Cno;

26、查询每门课程被选修的学生数
  select Cno, count(Sno) from C3_SC group by Cno;

27、查询出只选修了一门课程的全部学生的学号和姓名
    select C3_SC.Sno,C1_Student.Sname,count(Cno) as 选课数

from C3_SC,C1_Student

where C3_SC.Sno = C1_Student.Sno group by C3_SC.Sno,C1_Student.Sname having COUNT(Cno)=1;

28、查询男生、女生人数
    select COUNT(Ssex) as 男生人数 from C1_Student group by Ssex having Ssex='男';

select COUNT(Ssex) as 女生人数 from C1_Student group by Ssex having Ssex='女';

29、查询姓“张”的学生名单
    select Sname,Sno,Ssex,Sage,Sdept,Sid,Sdate

from C1_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(*) as 同名人数

from C1_Student

group by Sname having COUNT(*)>1;

31、1999年出生的学生名单(注：Student表中Sage列的类型是datetime)
        select Sname,Sno,Ssex,Sage,Sdept,Sid,Sdate

from C1_Student

where Sage=(select DATENAME(YEAR,GETDATE())-1999);

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 Cno,Avg(Grade) from C3_SC group by Cno order by Avg(Grade),Cno    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 C3_SC.Sno,Sname,AVG(Grade)

from C1_Student,C3_SC

where C1_Student.Sno = C3_SC.Sno group by C3_SC.Sno,Sname having   AVG(Grade)>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(Grade,0)

from C1_Student,C2_Course,C3_SC

where C3_SC.Sno=C1_Student.Sno and C2_Course.Cno=C3_SC.Cno and C2_Course.Cname='高等数学' and C3_SC.Grade<80;

35、查询所有学生的选课情况；
       select C3_SC.Sno,Sname,C2_Course.Cno,Cname

from C1_Student,C2_Course,C3_SC

where C1_Student.Sno = C3_SC.Sno and C2_Course.Cno = C3_SC.Cno

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 Sname,Cname,Grade

from C1_Student,C2_Course,C3_SC

where C1_Student.Sno=C3_SC.Sno and C2_Course.Cno=C3_SC.Cno and C3_SC.Grade>70;

 
37、查询不及格的课程，并按课程号从大到小排列
    select distinct Cno

from C3_SC where Grade<80 order by Cno;

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 C1_Student.Sno,Sname,Grade

from C1_Student,C3_SC

where C1_Student.Sno = C3_SC.Sno and Grade>80 and Cno = '0000000000';

39、求选了课程的学生人数
         select COUNT(*) as 已选课程学生人数 from C3_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 C1_Student.Sname,Grade

from C1_Student,C3_SC,C2_Course C,C4_Teacher

where C1_Student.Sno=C3_SC.Sno and C3_SC.Cno=C.Cno and

C.Tno=C4_Teacher.Tno and C4_Teacher.Tname='范平' and C3_SC.Grade=(select max(Grade)from C3_SC where Cno=C.Cno );

41、查询各个课程及相应的选修人数
    select C3_SC.Cno,COUNT(*) as 选修人数 from C3_SC group by Cno;

 
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.Sno,A.Cno,B.Grade from C3_SC A  ,C3_SC B where A.Grade=B.Grade and A.Cno <>B.Cno ;

43、查询每门功成绩最好的前两名
    SELECT t1.Sno as 学生ID,t1.Cno as 课程ID,Grade as 分数

FROM C3_SC t1

WHERE Grade IN (SELECT TOP 2 Grade

FROM C3_SC

WHERE t1.Cno= Cno

ORDER BY Grade DESC

)

ORDER BY t1.Cno;

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  Cno as 课程号,count(*) as 人数

from  C3_SC

group  by  Cno

order  by  count(*) desc,Cno

45、检索至少选修两门课程的学生学号
        select Sno

from C3_SC

group by Sno

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 Cno,Cname

from C2_Course

where Cno in(select Cno from C3_SC group by Cno);

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 C1_Student

where Sno not in

(select Sno

from C2_Course,C3_SC,C4_Teacher

where C2_Course.Tno=C4_Teacher.Tno and C3_SC.Cno=C2_Course.Cno and Tname='陈博');

 
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 Sno,avg(isnull(Grade,0)) as 平均成绩

from C3_SC where Sno in

(select Sno from C3_SC where

Grade <60 group by Sno having count(*)>2)group by Sno;

49、检索“004”课程分数小于60，按分数降序排列的同学学号
    select Sno,Grade from C3_SC where Cno='0000000001'and Grade <60 order by Grade desc;

 
50、删除“002”同学的“001”课程的成绩
delete from C3_SC where Sno='0000007'and Cno='0000000000';

文章为作者自己练习作业，如若有错误，欢迎留言讨论，博主很喜欢和大家共同进步哟~~~~

另外，文章为博主自己电脑所做，上传目的只是为了可以帮助到需要帮助的人，电脑信息以及数据库中信息均未打码，还望各位大侠不要恶意攻击哈~~~~~~~~~~~

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