Student(S,Sname,Sage,Ssex) 學生表
Course(C,Cname,T) 課程表
SC(S,C,score) 成績表
Teacher(T,Tname) 教師表
問題：
1、查詢“001”課程比“002”課程成績高的所有學生的學號；
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、查詢平均成績大於60分的同學的學號和平均成績；
select S,avg(score)
from sc
group by S having avg(score) >60;
3、查詢所有同學的學號、姓名、選課數、總成績；
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、查詢姓“李”的老師的個數；
select count(distinct(Tname))
from Teacher
where Tname like '李%';
5、查詢沒學過“葉平”老師課的同學的學號、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='葉平');
6、查詢學過“001”並且也學過編號“002”課程的同學的學號、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、查詢學過“葉平”老師所教的所有課的同學的學號、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='葉平' group by S having count(SC.C)=(select count(C) from Course,Teacher where Teacher.T=Course.T and Tname='葉平'));
8、查詢課程編號“002”的成績比課程編號“001”課程低的所有同學的學號、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、查詢所有課程成績小於60分的同學的學號、姓名；
select S,Sname
from Student
where S not in (select Student.S from Student,SC where S.S=SC.S and score>60);
10、查詢沒有學全所有課的同學的學號、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、查詢至少有一門課與學號爲“1001”的同學所學相同的同學的學號和姓名；
select S,Sname from Student,SC where Student.S=SC.S and C in select C from SC where S='1001';
12、查詢至少學過學號爲“001”同學所有一門課的其他同學學號和姓名；
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“葉平”老師教的課的成績都更改爲此課程的平均成績；
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='葉平');
14、查詢和“1002”號的同學學習的課程完全相同的其他同學學號和姓名；
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、刪除學習“葉平”老師課的SC表記錄；
Delect SC
from course ,Teacher
where Course.C=SC.C and Course.T= Teacher.T and Tname='葉平';
16、向SC表中插入一些記錄，這些記錄要求符合以下條件：沒有上過編號“003”課程的同學學號、2、
號課的平均成績；
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、按平均成績從高到低顯示所有學生的“數據庫”、“企業管理”、“英語”三門的課程成績，按如下形式顯示： 學生ID,,數據庫,企業管理,英語,有效課程數,有效平均分
SELECT S as 學生ID
,(SELECT score FROM SC WHERE SC.S=t.S AND C='004') AS 數據庫
,(SELECT score FROM SC WHERE SC.S=t.S AND C='001') AS 企業管理
,(SELECT score FROM SC WHERE SC.S=t.S AND C='006') AS 英語
,COUNT(*) AS 有效課程數, AVG(t.score) AS 平均成績
FROM SC AS t
GROUP BY S
ORDER BY avg(t.score)
18、查詢各科成績最高和最低的分：以如下形式顯示：課程ID，最高分，最低分
SELECT L.C As 課程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、按各科平均成績從低到高和及格率的百分數從高到低順序
SELECT t.C AS 課程號,max(course.Cname)AS 課程名,isnull(AVG(score),0) AS 平均成績
,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分數
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、查詢如下課程平均成績和及格率的百分數(用"1行"顯示):
企業管理（001），馬克思（002），OO&UML （003），數據庫（004）
SELECT SUM(CASE WHEN C ='001' THEN score ELSE 0 END)/SUM(CASE C WHEN '001' THEN 1 ELSE 0 END) AS 企業管理平均分
,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 企業管理及格百分數
,SUM(CASE WHEN C = '002' THEN score ELSE 0 END)/SUM(CASE C WHEN '002' THEN 1 ELSE 0 END) AS 馬克思平均分
,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 馬克思及格百分數
,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及格百分數
,SUM(CASE WHEN C = '004' THEN score ELSE 0 END)/SUM(CASE C WHEN '004' THEN 1 ELSE 0 END) AS 數據庫平均分
,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 數據庫及格百分數
FROM SC
21、查詢不同老師所教不同課程平均分從高到低顯示
SELECT max(Z.T) AS 教師ID,MAX(Z.Tname) AS 教師姓名,C.C AS 課程ＩＤ,MAX(C.Cname) AS 課程名稱,AVG(Score) AS 平均成績
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、查詢如下課程成績第 3 名到第 6 名的學生成績單：企業管理（001），馬克思（002），UML （003），數據庫（004）
[學生ID],[學生姓名],企業管理,馬克思,UML,數據庫,平均成績
SELECT DISTINCT top 3
SC.S As 學生學號,
Student.Sname AS 學生姓名 ,
T1.score AS 企業管理,
T2.score AS 馬克思,
T3.score AS UML,
T4.score AS 數據庫,
ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 總分
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、統計列印各科成績,各分數段人數:課程ID,課程名稱,[100-85],[85-70],[70-60],[ <60]
SELECT SC.C as 課程ID, Cname as 課程名稱
,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、查詢學生平均成績及其名次
SELECT 1+(SELECT COUNT( distinct 平均成績)
FROM (SELECT S,AVG(score) AS 平均成績
FROM SC
GROUP BY S
) AS T1
WHERE 平均成績 > T2.平均成績) as 名次,
S as 學生學號,平均成績
FROM (SELECT S,AVG(score) 平均成績
FROM SC
GROUP BY S
) AS T2
ORDER BY 平均成績 desc;
25、查詢各科成績前三名的記錄:(不考慮成績並列情況)
SELECT t1.S as 學生ID,t1.C as 課程ID,Score as 分數
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、查詢每門課程被選修的學生數
select c,count(S) from sc group by C;
27、查詢出只選修了一門課程的全部學生的學號和姓名
select SC.S,Student.Sname,count(C) AS 選課數
from SC ,Student
where SC.S=Student.S group by SC.S ,Student.Sname having count(C)=1;
28、查詢男生、女生人數
Select count(Ssex) as 男生人數 from Student group by Ssex having Ssex='男';
Select count(Ssex) as 女生人數 from Student group by Ssex having Ssex='女'；
29、查詢姓“張”的學生名單
SELECT Sname FROM Student WHERE Sname like '張%';
30、查詢同名同性學生名單，並統計同名人數
select Sname,count(*) from Student group by Sname having count(*)>1;;
31、1981年出生的學生名單(注：Student表中Sage列的類型是datetime)
select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age
from student
where CONVERT(char(11),DATEPART(year,Sage))='1981';
32、查詢每門課程的平均成績，結果按平均成績升序排列，平均成績相同時，按課程號降序排列
Select C,Avg(score) from SC group by C order by Avg(score),C DESC ;
33、查詢平均成績大於85的所有學生的學號、姓名和平均成績
select Sname,SC.S ,avg(score)
from Student,SC
where Student.S=SC.S group by SC.S,Sname having avg(score)>85;
34、查詢課程名稱爲“數據庫”，且分數低於60的學生姓名和分數
Select Sname,isnull(score,0)
from Student,SC,Course
where SC.S=Student.S and SC.C=Course.C and Course.Cname='數據庫'and score <60;
35、查詢所有學生的選課情況；
SELECT SC.S,SC.C,Sname,Cname
FROM SC,Student,Course
where SC.S=Student.S and SC.C=Course.C ;
36、查詢任何一門課程成績在70分以上的姓名、課程名稱和分數；
SELECT distinct student.S,student.Sname,SC.C,SC.score
FROM student,Sc
WHERE SC.score>=70 AND SC.S=student.S;
37、查詢不及格的課程，並按課程號從大到小排列
select c from sc where scor e <60 order by C ;
38、查詢課程編號爲003且課程成績在80分以上的學生的學號和姓名；
select SC.S,Student.Sname from SC,Student where SC.S=Student.S and Score>80 and C='003';
39、求選了課程的學生人數
select count(*) from sc;
40、查詢選修“葉平”老師所授課程的學生中，成績最高的學生姓名及其成績
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='葉平' and SC.score=(select max(score)from SC where C=C.C );
41、查詢各個課程及相應的選修人數
select count(*) from sc group by C;
42、查詢不同課程成績相同的學生的學號、課程號、學生成績
select distinct A.S,B.score from SC A ,SC B where A.Score=B.Score and A.C <>B.C ;
43、查詢每門功成績最好的前兩名
SELECT t1.S as 學生ID,t1.C as 課程ID,Score as 分數
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、統計每門課程的學生選修人數（超過10人的課程才統計）。要求輸出課程號和選修人數，查詢結果按人數降序排列，查詢結果按人數降序排列，若人數相同，按課程號升序排列
select C as 課程號,count(*) as 人數
from sc
group by C
order by count(*) desc,c
45、檢索至少選修兩門課程的學生學號
select S
from sc
group by s
having count(*) > = 2
46、查詢全部學生都選修的課程的課程號和課程名
select C,Cname
from Course
where C in (select c from sc group by c)
47、查詢沒學過“葉平”老師講授的任一門課程的學生姓名
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='葉平');
48、查詢兩門以上不及格課程的同學的學號及其平均成績
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、檢索“004”課程分數小於60，按分數降序排列的同學學號
select S from SC where C='004'and score <60 order by score desc;
50、刪除“002”同學的“001”課程的成績
delete from Sc where S='001'and C='001';