爱华网Student(S#,Sname,Sage,Ssex)学生表S#：学号；Sname：学生姓名；Sage：学生年龄；Ssex：学生性别
Course(C#,Cname,T#)课程表C#,课程编号；Cname：课程名字；T#：教师编号
SC(S#,C#,score)成绩表S#：学号；C#,课程编号；score：成绩
Teacher(T#,Tname)教师表T#：教师编号； Tname：教师名字
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 whereC#='001') a,(select s#,score
from SC where C#='002') b
where a.score>b.score anda.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；
selectS#,avg(score)
fromsc
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；
selectStudent.S#,Student.Sname,count(SC.C#),sum(score)
from Student left Outer join SC onStudent.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；
selectStudent.S#,Student.Sname
fromStudent
where S# notin (select distinct( SC.S#) from SC,Course,Teacherwhere 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,SCwhere Student.S#=SC.S# and SC.C#='001'and exists( Select * from SCas 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 ,Teacherwhere SC.C#=Course.C# and Teacher.T#=Course.T# andTeacher.Tname='叶平' group by S# having count(SC.C#)=(selectcount(C#) from Course,Teacher whereTeacher.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 (selectStudent.S#,Student.Sname,score ,(select score from SC SC_2 whereSC_2.S#=Student.S# and SC_2.C#='002') score2
from Student,SC where Student.S#=SC.S# andC#='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# fromStudent,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；
selectStudent.S#,Student.Sname
fromStudent,SC
whereStudent.S#=SC.S# group byStudent.S#,Student.Sname having count(C#) <(selectcount(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；
selectS#,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；
selectdistinct SC.S#,Sname
fromStudent,SC
whereStudent.S#=SC.S# and C# in (select C# from SC whereS#='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 SCset score=(select avg(SC_2.score)
from SCSC_2
whereSC_2.C#=SC.C# ) from Course,Teacher where Course.C#=SC.C# andCourse.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；
DelectSC
from course,Teacher
whereCourse.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 SCselect S#,'002',(Select avg(score)
from SCwhere C#='002') from Student where S# not in (Select S# from SCwhere 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 ASt
GROUP BYS#
ORDER BYavg(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 WHENisnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS及格百分数
FROM SCT,Course
wheret.C#=course.C#
GROUP BYt.C#
ORDER BY 100* SUM(CASE WHENisnull(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）
SELECTSUM(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 THEN1 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 THEN1 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 THEN1 ELSE 0 END)/SUM(CASE WHEN C# = '003' THEN 1 ELSE 0 END) ASUML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 THEN1 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 AST,Course AS C ,Teacher AS Z
whereT.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-]
FROMSC,Course
whereSC.C#=Course.C#
GROUP BYSC.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 (SELECTS#,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
Selectcount(Ssex) as 男生人数 from Student group by Ssex havingSsex='男';
Selectcount(Ssex) as 女生人数 from Student group by Ssex havingSsex='女'；
29、查询姓“张”的学生名单
SELECT SnameFROM 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 bySname having count(*)>1;;
31、1981年出生的学生名单(注：Student表中Sage列的类型是datetime)
selectSname, CONVERT(char (11),DATEPART(year,Sage)) asage
fromstudent
whereCONVERT(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
SelectC#,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
selectSname,SC.S# ,avg(score)
fromStudent,SC
whereStudent.S#=SC.S# group by SC.S#,Snamehavingavg(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
SelectSname,isnull(score,0)
fromStudent,SC,Course
whereSC.S#=Student.S# and SC.C#=Course.C# andCourse.Cname='数据库'and score <60;
35、查询所有学生的选课情况；
SELECTSC.S#,SC.C#,Sname,Cname
FROMSC,Student,Course
whereSC.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 distinctstudent.S#,student.Sname,SC.C#,SC.score
FROMstudent,Sc
WHERESC.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；
selectSC.S#,Student.Sname from SC,Student where SC.S#=Student.S# andScore>80 and C#='003';
39、求选了课程的学生人数
selectcount(*) 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
selectStudent.Sname,score
fromStudent,SC,Course C,Teacher
whereStudent.S#=SC.S# and SC.C#=C.C# and C.T#=Teacher.T# andTeacher.Tname='叶平' and SC.score=(select max(score)from SC whereC#=C.C# );
41、查询各个课程及相应的选修人数
selectcount(*) 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.scorefrom 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 groupby 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 Snamefrom Student where S# not in (select S# from Course,Teacher,SCwhere Course.T#=Teacher.T# and SC.C#=course.C# andTname='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
selectS#,avg(isnull(score,0)) from SC where S# in (select S# from SCwhere score <60 group by S# havingcount(*)>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 scoredesc;
50、删除“002”同学的“001”课程的成绩
delete from Sc where S#='002'and C#='001';
