SQL資料庫面試題以及答案
Student(Sno,Sname,Sage,Ssex) 學生表 Sno：學號；Sname：學生姓名；Sage：學生年齡；Ssex：學生性別
Course(Cno,Cname,Tno) 課程表 Cno,課程編號；Cname：課程名字；Tno：教師編號
SC(Sno,Cno,score) 成績表 Sno：學號；Cno,課程編號；score：成績
Teacher(Tno,Tname) 教師表 Tno：教師編號； Tname：教師名字
建立資料表：
create table Student(
Sno varchar(10) not null primary key,
Sname varchar(20) null,
Sage int null,
Ssex varchar(2) null
)
create table Course(
Cno varchar(10) not null primary key,
Cname varchar(20) null,
Tno varchar(20) null
)
create table SC(
Sno varchar(10) not null primary key,
Cno varchar(10) not null primary key,
score int null
)
create table Teacher(
Tno varchar(20) primary key not null,
Tname varchar(20) null
)
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.Sno from (select Sno,score from SC where Cno=`001`) a,(select Sno,score
from SC where Cno=`002`) b
where a.score>b.score and a.Sno=b.Sno;
2、查詢平均成績大於60分的同學的學號和平均成績；
select Sno,avg(score)
from sc
group by Sno having avg(score) >60;
3、查詢所有同學的學號、姓名、選課數、總成績；
select Student.Sno,Student.Sname,count(SC.Cno),sum(score)
from Student left Outer join SC on Student.Sno=SC.Sno
group by Student.Sno,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.Sno,Student.Sname
from Student
where Sno not in (select distinct( SC.Sno) from SC,Course,Teacher where SC.Cno=Course.Cno and Teacher.Tno=Course.Tno 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.Sno,Student.Sname from Student,SC where Student.Sno=SC.Sno and SC.Cno=`001`and exists( Select * from SC as SC_2 where SC_2.Sno=SC.Sno and SC_2.Cno=`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 Sno,Sname
from Student
where Sno in (select Sno from SC ,Course ,Teacher where SC.Cno=Course.Cno and Teacher.Tno=Course.Tno and Teacher.Tname=`葉平` group by Sno having count(SC.Cno)=(select count(Cno) from Course,Teacher where Teacher.Tno=Course.Tno 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 Sno,Sname from (select Student.Sno,Student.Sname,score ,(select score from SC SC_2 where SC_2.Sno=Student.Sno and SC_2.Cno=`002`) score2
from Student,SC where Student.Sno=SC.Sno and Cno=`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 Sno,Sname
from Student
where Sno not in (select Student.Sno from Student,SC where S.Sno=SC.Sno and score>60);
10、查詢沒有學全所有課的同學的學號、姓名；
select Student.Sno,Student.Sname
from Student,SC
where Student.Sno=SC.Sno group by Student.Sno,Student.Sname having count(Cno) <(select count(Cno) from Course);
11、查詢至少有一門課與學號為“1001”的同學所學相同的同學的學號和姓名；
select Sno,Sname from Student,SC where Student.Sno=SC.Sno and Cno in select Cno from SC where Sno=`1001`;
12、查詢至少學過學號為“001”同學所有一門課的其他同學學號和姓名；
select distinct SC.Sno,Sname
from Student,SC
where Student.Sno=SC.Sno and Cno in (select Cno from SC where Sno=`001`);
13、把“SC”表中“葉平”老師教的課的成績都更改為此課程的平均成績；
update SC set score=(select avg(SC_2.score)
from SC SC_2
where SC_2.Cno=SC.Cno ) from Course,Teacher where Course.Cno=SC.Cno and Course.Tno=Teacher.Tno 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 Sno from SC where Cno in (select Cno from SC where Sno=`1002`)
group by Sno having count(*)=(select count(*) from SC where Sno=`1002`);
15、刪除學習“葉平”老師課的SC表記錄；
Delect SC
from course ,Teacher
where Course.Cno=SC.Cno and Course.Tno= Teacher.Tno 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 Sno,`002`,(Select avg(score)
from SC where Cno=`002`) from Student where Sno not in (Select Sno from SC where Cno=`002`);
17、按平均成績從高到低顯示所有學生的“資料庫”、“企業管理”、“英語”三門的課程成績，按如下形式顯示： 學生ID,,資料庫,企業管理,英語,有效課程數,有效平均分
SELECT Sno as 學生ID
,(SELECT score FROM SC WHERE SC.Sno=t.Sno AND Cno=`004`) AS 資料庫
,(SELECT score FROM SC WHERE SC.Sno=t.Sno AND Cno=`001`) AS 企業管理
,(SELECT score FROM SC WHERE SC.Sno=t.Sno AND Cno=`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 Sno
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.Cno As 課程ID,L.score AS 最高分,R.score AS 最低分
FROM SC L ,SC AS R
WHERE L.Cno = R.Cno and
L.score = (SELECT MAX(IL.score)
FROM SC AS IL,Student AS IM
WHERE L.Cno = IL.Cno and IM.Sno=IL.Sno
GROUP BY IL.Cno)
AND
R.Score = (SELECT MIN(IR.score)
FROM SC AS IR
WHERE R.Cno = IR.Cno
GROUP BY IR.Cno
);
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.Cno 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.Cno=course.Cno
GROUP BY t.Cno
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），資料庫（004）
SELECT SUM(CASE WHEN Cno =`001` THEN score ELSE 0 END)/SUM(CASE Cno WHEN `001` THEN 1 ELSE 0 END) AS 企業管理平均分
,100 * SUM(CASE WHEN Cno = `001` AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN Cno = `001` THEN 1 ELSE 0 END) AS 企業管理及格百分數
,SUM(CASE WHEN Cno = `002` THEN score ELSE 0 END)/SUM(CASE Cno WHEN `002` THEN 1 ELSE 0 END) AS 馬克思平均分
,100 * SUM(CASE WHEN Cno = `002` AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN Cno = `002` THEN 1 ELSE 0 END) AS 馬克思及格百分數
,SUM(CASE WHEN Cno = `003` THEN score ELSE 0 END)/SUM(CASE Cno WHEN `003` THEN 1 ELSE 0 END) AS UML平均分
,100 * SUM(CASE WHEN Cno = `003` AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN Cno = `003` THEN 1 ELSE 0 END) AS UML及格百分數
,SUM(CASE WHEN Cno = `004` THEN score ELSE 0 END)/SUM(CASE Cno WHEN `004` THEN 1 ELSE 0 END) AS 資料庫平均分
,100 * SUM(CASE WHEN Cno = `004` AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN Cno = `004` THEN 1 ELSE 0 END) AS 資料庫及格百分數
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.Tno) AS 教師ID,MAX(Z.Tname) AS 教師姓名,C.Cno 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.Cno=C.Cno and C.Tno=Z.Tno
GROUP BY C.Cno
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），資料庫（004）
[學生ID],[學生姓名],企業管理,馬克思,UML,資料庫,平均成績
SELECT DISTINCT top 3
SC.Sno 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 資料庫,
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.Sno = T1.Sno AND T1.Cno = `001`
LEFT JOIN SC AS T2
ON SC.Sno = T2.Sno AND T2.Cno = `002`
LEFT JOIN SC AS T3
ON SC.Sno = T3.Sno AND T3.Cno = `003`
LEFT JOIN SC AS T4
ON SC.Sno = T4.Sno AND T4.Cno = `004`
WHERE student.Sno=SC.Sno 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.Sno = T1.Sno AND T1.Cno = `k1`
LEFT JOIN sc AS T2
ON sc.Sno = T2.Sno AND T2.Cno = `k2`
LEFT JOIN sc AS T3
ON sc.Sno = T3.Sno AND T3.Cno = `k3`
LEFT JOIN sc AS T4
ON sc.Sno = T4.Sno AND T4.Cno = `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.Cno 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.Cno=Course.Cno
GROUP BY SC.Cno,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 Sno,AVG(score) AS 平均成績
FROM SC
GROUP BY Sno
) AS T1
WHERE 平均成績 > T2.平均成績) as 名次,
Sno as 學生學號,平均成績
FROM (SELECT Sno,AVG(score) 平均成績
FROM SC
GROUP BY Sno
) 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.Sno as 學生ID,t1.Cno as 課程ID,Score as 分數
FROM SC t1
WHERE score IN (SELECT TOP 3 score
FROM SC
WHERE t1.Cno= Cno
ORDER BY score DESC
)
ORDER BY t1.Cno;
26、查詢每門課程被選修的學生數
select Cno,count(Sno) from sc group by Cno;
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.Sno,Student.Sname,count(Cno) AS 選課數
from SC ,Student
where SC.Sno=Student.Sno group by SC.Sno ,Student.Sname having count(Cno)=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列的型別是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 Cno,Avg(score) from SC group by Cno order by Avg(score),Cno 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.Sno ,avg(score)
from Student,SC
where Student.Sno=SC.Sno group by SC.Sno,Sname having avg(score)>85;
34、查詢課程名稱為“資料庫”，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.Sno=Student.Sno and SC.Cno=Course.Cno and Course.Cname=`資料庫`and score <60;
35、查詢所有學生的選課情況；
SELECT SC.Sno,SC.Cno,Sname,Cname
FROM SC,Student,Course
where SC.Sno=Student.Sno and SC.Cno=Course.Cno ;
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.Sno,student.Sname,SC.Cno,SC.score
FROM student,Sc
WHERE SC.score>=70 AND SC.Sno=student.Sno;
37、查詢不及格的課程，並按課程號從大到小排列
select Cno from sc where scor e <60 order by Cno ;
38、查詢課程編號為003且課程成績在80分以上的學生的學號和姓名；
select SC.Sno,Student.Sname from SC,Student where SC.Sno=Student.Sno and Score>80 and Cno=`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.Sno=SC.Sno and SC.Cno=C.Cno and C.Tno=Teacher.Tno and Teacher.Tname=`葉平` and SC.score=(select max(score)from SC where Cno=C.Cno );
41、查詢各個課程及相應的選修人數
select count(*) from sc group by Cno;
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.Sno,B.score from SC A ,SC B where A.Score=B.Score and A.Cno <>B.Cno ;
43、查詢每門功成績最好的前兩名
SELECT t1.Sno as 學生ID,t1.Cno as 課程ID,Score as 分數
FROM SC t1
WHERE score IN (SELECT TOP 2 score
FROM SC
WHERE t1.Cno= Cno
ORDER BY score DESC
)
ORDER BY t1.Cno;
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 Cno as 課程號,count(*) as 人數
from sc
group by Cno
order by count(*) desc,Cno
45、檢索至少選修兩門課程的學生學號
select Sno
from sc
group by Sno
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 Cno,Cname
from Course
where Cno in (select Cno from sc group by Cno)
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 Sno not in (select Sno from Course,Teacher,SC where Course.Tno=Teacher.Tno and SC.Cno=course.Cno 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 Sno,avg(isnull(score,0)) from SC where Sno in (select Sno from SC where score <60 group by Sno having count(*)>2)group by Sno;
49、檢索“004”課程分數小於60，按分數降序排列的同學學號
select Sno from SC where Cno=`004`and score <60 order by score desc;