经典SQL面试题.docx

Student(Sid,Sname,Sage,Sse*) 学生表
CREATE TABLE student (
sid varchar(10) NOT NULL,
sName varchar(20) DEFAULT NULL,
sAge datetime DEFAULT ' 1980-10-12 23:12:36',
sSe* varchar(10) DEFAULTNULL,
PRIMARY KEY (sid)
)ENGINE=InnoDBDEFAULTCHARSET=utf8;
Course(Cid,ame,Tid) 课程表
CREATE TABLE course (

cid varchar(10) NOT NULL,
ame varchar(10) DEFAULT NULL,
tid int(20) DEFAULT NULL,
PRIMARY KEY (cid)
)ENGINE=InnoDB DEFAULT CHARSET=utf8; SC(Sid,Cid,score)成绩表
CREATE TABLE sc (
sid varchar(10) DEFAULTNULL,
cid varchar(10) DEFAULTNULL,
score int(10) DEFAULT NULL
)ENGINE=InnoDB DEFAULT CHARSET=utf8; Teacher(Tid,Tname)教师表
CREATE TABLE taacher (

tid int(10) DEFAULT NULL,
tName
varchar(10) DEFAULT
NULL

)ENGINE=InnoDB DEFAULT CHARSET=utf8;
数据：〔MySQL 〕
insert into taacher(tid,tName) values (1,教师')，(斓以琛')，(叶平')；
insert into student(sid,sName,sAge,sSe*) values ('11',三丰'，' 198010-12 23:12:36','男')，('12'无极'，'1
995-10-12 23:12:36','男')，('13'奎'，' 1992-10-12 23:12:36','女')，('14'元'宝'，' 1980-10-12 23:12:36',女'),('
15','世明',' 1981-10-12 23:12:36','男')，('16六'，' 1986-10-12 23:12:36','男')，('17田'七'，'1981-10-12 2
3:12:36',女');
insert into sc(sid,cid,score)values (' 1',' 1',80),(' 1',' 2',60),(' 1',' 3',75),(' 2',' 1',85),(' 2',' 2',70),(' 3','4',1),(' 3',' 1',90),(' 3',' 2',55),(' 4',' 2',65),(' 4',' 3',60);
insert into course(cid,ame,tid) values ('1',企业管理'，3),(' 2马克思'，3),(' 3','UML',2),('0(数'据库'，1),
(' 5',英语'，1);
问题:
1、查询"1 课程比"2 课程成绩高的所有学生的**;
select a.Sid from (selectsid,score from SC where Cid='1') a,(selectsid,scorefrom SC where Cid='2') b
where a.score>b.score and a.sid=b.sid;
2、查询平均成绩大于60分的同学的**和平均成绩；
select Sid,avg(score)

from scgroup by Sid having avg(score) >60;
3、查询所有同学的**、、选课数、总成绩;
select Student.Sid,Student.Sname,count(SC.Cid),sum(score)from Student leftOuter join SC on Student.Sid=SC.Sidgroup by Student.Sid,Sname
4、查询姓"的教师的个数;
select count(distinct(Tname))from Teacherwhere Tname like'%';
5、查询没学过"叶平 教师课的同学的**、；
select Student.Sid,Student.Snamefrom Studentwhere Sid not in (select distinct(SC.Sid) from SC,Course,Teacher where SC.Cid=Course.Cid and Teacher.Tid=Course.Tid and Teacher.Tname=' 叶平');
6、查询学过"1 并且也学过编号"2 课程的同学的**、；
select Student.Sid,Student.Sname from Student,SC where Student.Sid=SC.Sid and SC.Cid='1'and e
*ists(Select * from SC as SC_2 where SC_2.Sid=SC.Sid and SC_2.Cid=' 2');
7、查询学过"叶平 教师所教的所有课的同学的**、；
select Sid,Snamefrom Studentwhere Sid in (selectSid from SC ,Course ,Teacher where SC.Cid=Course.Cid and Teacher.Tid=Course.Tid and Teacher.Tname=' 叶平'group by Sid having count(SC.Cid) = (select count(Cid) from Course,Teacher where Teacher.Tid=Course.Tid and Tname=' 叶平'));

8、查询课程编号"2 的成绩比课程编号"1 课程低的所有同学的**、；
Select Sid,Sname from (select Student.Sid,Student.Sname,score , (selects core from SC SC_2 where SC_2.Sid=Student.Sid and SC_2.Cid=' 2') score2
from Student,SC where Student.Sid=SC.Sid and Cid='1') S_2 where score2 ot in (select Student.Sid from Student,SC where S.Sid=SC.Sid and score>60);
10、查询没有学全所有课的同学的**、；
select Student.Sid,Student.Sname
from Student,SC
where Student.Sid=SC.Sid group by Student.Sid,Student.Sname having count(Cid) <(select count(Cid)from Course);
11、查询至少有一门课与**为"11 的同学所学一样的同学的**和；
select Sid,Sname from Student,SC where Student.Sid=SC.Sid and Cid in select Cid from SC where Sid='11';
12、查询至少学过**为"1 同学所有一门课的其他同学**和；
select distinct SC.Sid,Sname
from Student,SC
where Student.Sid=SC.Sid and Cid in (selectCid from SC where Sid='1');
13、把"SC表中"叶平教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.Cid=SC.Cid ) from Course,Teacher where Course.Cid=SC.Cid and Course.Tid=Teacher.Tid

and Teacher.Tname='叶平')；
14、查询和"12 号的同学学习的课程完全一样的其他同学**和；
select Sid from SC where Cid in (selectCid from SC where Sid=' 12')group by Sid having count(*) = (selectcount(*) from SC where Sid=' 12');
15、删除学习"叶平教师课的SC表记录;
Delect SCfrom course ,Teacherwhere Course.Cid=SC.Cid and Course.Tid= Teacher.Tid 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"3课程的同学**、2号课的平均成绩;
Insert SC select Sid,' 2',(Selecavg(score)
from SC where Cid=' 2') from Student where Sid not in (Select Sid from SC where Cid=' 2');
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
Sid as
学生ID
,(SELECT
score
FROM
SC
WHERE
SC.Sid=t.Sid
AND
Cid=' 4')
AS
数据库
,(SELECT
score
FROM
SC
WHERE
SC.Sid=t.Sid
AND
Cid='1')
AS
企业管理
,(SELECT
score
FROM
SC
WHERE
SC.Sid=t.Sid
AND
Cid=' 6')
AS
英语

,COUNT(*)
AS有效课程数，AVG(t.score) AS平均成绩

FROM
SC
AS t
GROUP
BY Sid
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.Cid As 课程 ID,L.score AS 最高分，R.score AS 最低分
FROM SC L ,SC AS R
WHERE L.Cid = R.Cid and
L.score = (SELECT MA*(IL.score)
FROM SC AS IL,Student AS IM
WHERE L.Cid = IL.Cid and IM.Sid=IL.Sid
GROUP
BY IL.Cid)

AND
R.Score = (SELECT MIN(IR.score)
FROM
SC AS IR
WHERE
R.Cid = IR.Cid
GROUP
BY IR.Cid
);
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.Cid AS 课程号,ma*(course.ame)AS 课程名,isnull(AVG(score),0)AS 平均成绩
,1
* 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.Cid=course.Cid
GROUP
BY t.Cid
ORDER
BY 1 * 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〔1〕，
马克思〔2〕，OO&UML 〔 3〕，数据库〔4〕

Cid WHEN '1' THEN
SELECT SUM(CASE WHEN Cid ='1' THEN score ELSE 0 END)/SUM(CASE

1 ELSE 0 END) AS企业管理平均分
,1 * SUM(CASE WHEN
Cid = '1' AND score >= 60 THEN 1 ELSE
0 END)/SUM(CASE
WHEN
Cid
'1' THEN 1 ELSE 0
END) AS企业管理及格百分数
,SUM(CASE WHEN Cid
'2' THEN score ELSE 0
END)/SUM(CASE
Cid WHEN '2'
THEN 1
ELSE
0 END) AS马克思平均分
,1 * SUM(CASE
WHEN
Cid = ' 2' AND score >=
60 THEN 1 ELSE
0 END)/SUM(CASE
WHEN
Cid
' 2' THEN 1
ELSE 0
END) AS马克思及格百分数
,SUM(CASE WHEN
Cid
'3' THEN score ELSE 0
END)/SUM(CASE
Cid WHEN ' 3'
THEN 1
ELSE

0 END) AS UML
平均分
,1 * SUM(CASE
WHEN
Cid = '3' AND score >=
60 THEN 1 ELSE
0 END)/SUM(CASE
WHEN
Cid
' 3' THEN 1
ELSE 0
END) AS UML及格百分数
,SUM(CASE WHEN
Cid
'4' THEN score ELSE 0
END)/SUM(CASE
Cid WHEN '4'
THEN 1
ELSE
0 END) AS数据库平均分
,1 * SUM(CASE WHEN
Cid = '4' AND score >=
60 THEN 1 ELSE
0 END)/SUM(CASE
WHEN
Cid
' 4' THEN 1 ELSE 0
END) AS数据库及格百分数
FROM SC
21、查询不同教师所教不同课程平均分从高到低显示
SELECT ma*(Z.Tid) AS
教师 ID,MA*(Z.Tname) AS 教师，C.Cid AS 课程 I D,MA*(C.ame) AS
课程名称,AVG
(Score) AS平均成绩
FROM
SC AS T,Course
AS C ,Teacher AS Z
where
T.Cid=C.Cid and
C.Tid=Z.Tid
GROUP
BY C.Cid
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〔1〕，

马克思〔2〕，UML
〔 3〕，数据库〔4

［学生ID］,学生］企业管理,马克思,UML,数据库，平均成绩
SELECT DISTINCT top 3
SC.Sid As 学生**
Student.Sname AS 学生，
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.Sid
Tl.Sid AND
T1.Cid = '1'
LEFT JOIN
SC AS T2
ON SC.Sid

T2.Sid AND
T2.Cid = ' 2'
LEFT JOIN
SC AS T3
ON SC.Sid
T3.Sid AND
T3.Cid = ' 3'
LEFT JOIN
SC AS T4
ON SC.Sid
T4.Sid AND
T4.Cid = ' 4'

WHERE student.Sid=SC.Sid 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.Sid = Tl.Sid AND
T1.Cid = 'k1'

LEFT JOIN sc AS T2
ON sc.Sid = T2.Sid AND
T2.Cid = 'k2'

LEFT JOIN sc AS T3
ON sc.Sid = T3.Sid AND
T3.Cid = 'k3'

LEFT JOIN sc AS T4
ON sc.Sid = T4.Sid AND
T4.Cid = 'k4'

ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DES
C);
23、统计列印各科成绩，各分数段人数:课程ID，课程名称，[1-85],[85-70],[70
-60],[ <60]
SELECT SC.Cid as
课程 ID, ame as
课程名称
,SUM(CASE
WHEN
score
BETWEEN
85
AND
1 THEN
1 ELSE
0 END)
AS
[1 - 85]
,SUM(CASE
WHEN
score
BETWEEN
70
AND
85
THEN
ELSE
0 END)
AS
[85 - 70]
,SUM(CASE
WHEN
score
BETWEEN
60
AND
70
THEN
ELSE
0 END)
AS
[70 - 60]
,SUM(CASE
WHEN
score
< 60 THEN
ELSE
END)
AS
[60 -]
FROM
SC,Course
where
SC.Cid=Course.Cid
GROUP
BY SC.Cid,ame;

24、查询学生平均成绩及其名次

SELECT 1+(SELECT COUNT( distinct 平均成绩)
FROM (SELECT Sid,AVG(score) AS 平均成绩
FROM SC
GROUP BY Sid
)AS T1
WHERE平均成绩＞ T2 .平均成绩)as名次，
Sid as学生**,平均成绩
FROM (SELECT Sid,AVG(score)平均成绩
FROM SC
GROUP BY Sid
)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.Sid as 学生 ID,t1.Cid as 课程 ID,Score as 分数
FROM SC t1
WHERE score IN (SELECT TOP 3 score
FROM SC
WHERE t1.Cid= Cid
:DERBYscore DESC
ORDER BY t1.Cid;
26、查询每门课程被选修的学生数
select cid,count(Sid) from sc group by Cid;
27、查询出只选修了一门课程的全部学生的**和
AS选课数
select SC.Sid,Student.Sname,count(Cid)from SC ,Student
where SC.Sid=Student.Sid group by SC.Sid , Student.Sname having count(Cid)=1;
28、查询男生、女生人数
Select count(Sse*) as 男生人数 from Student group by Sse* having Sse*='男'；
Select count(Sse*) as 女生人数 from Student group by Sse* having Sse*='女'；
29、查询姓"的学生
SELECT Sname FROM Student WHERE Sname like'%';
30、查询同名同性学生，并统计同名人数
select Sname,count(*) from Student group by Sname having count(*)>1;;
31、1981年出生的学生注：Student表中Sage列的类型是datetime)
select Sname, CONVERT(char (11),DATEPART(year,Sage)) as agefrom student
where CONVERTchar(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，平均成绩一样时，按课程号降序排列
Select Cid,Avg(score) from SC group by Cid order by Avg(score),Cid DESC ;
33、查询平均成绩大于85的所有学生的**、和平均成绩
select Sname,SC.Sid , avg(score)from Student,SC
where Student.Sid=SC.Sid group by SC.Sid,Sname having avg(score)>85;

34、查询课程名称为"数据库
，且分数低于60的学生和分数

Select Sname,isnull(score,0)

from Student,SC,Course
where
SC.Sid=Student.Sid and SC.Cid=Course.Cid and Course.ame='数据库'and score <60;
35、
查询所有学生的选课情况；

SELECT SC.Sid,SC.Cid,Sname,ame
FROM
SC,Student,Course
where
SC.Sid=Student.Sid and SCCid=Course.Cid ;
36、
查询任何一门课程成绩在70分以上的、课程名称和分数；

SELECT distinct student.Sid,student.Sname,SC.Cid,SC.score
FROM
student,Sc
WHERE
SC.score>=70 AND SC.Sid=student.Sid;
37、
查询不及格的课程，并按课程号从大到小排列

select cid from sc where scor e <60 order by Cid ;
38、查询课程编号为3且课程成绩在80分以上的学生的**和；
select SC.Sid,Student.Sname from SC,Student where SC.Sid=Student.Sid and Score>80 and Cid='3
39、
求选了课程的学生人数

select count(*) from sc;
40、查询选修"叶平 教师所授课程的学生中，成绩最高的学生及其成绩
select Student.Sname,score
from Student,SC,Course C,Teacher
where Student.Sid=SC.Sid and SC.Cid=C.Cid and C.Tid=Teacher.Tid and TeacherTname=' 叶平'and S
C.score=(select ma*(score)from SC where Cid=C.Cid );
41、查询各个课程及相应的选修人数
select count(*) from sc group by Cid;

42、查询不同课程成绩一样的学生的**、课程号、学生成绩
A.Score=B.Score and A.Cid <>B.Cid ;
分数
select distinct A.Sid,B.score from SC A , SC B where
43、查询每门功成绩最好的前两名
SELECT t1.Sid as 学生 ID,t1.Cid as 课程 ID,Score as
FROM SC t1
WHERE score IN (SELECT TOP 2 score
FROM SC
WHERE t1.Cid= Cid
ORDERBY score DESC
)
ORDERBY t1.Cid;
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，假设人数一样，按课程号升序排列
select Cid as 课程号，count(*) as 人数
from scgroup by Cid
order by count(*) desc,cid45、检索至少选修两门课程的学生**select Sidfrom scgroup by sidhaving count(*) > = 2
46、查询全部学生都选修的课程的课程号和课程名
select Cid,ame
from Coursewhere Cid in (selectcid from sc group by cid)
47、查询没学过"叶平教师讲授的任一门课程的学生
select Sname from Student where Sid not in (selectSid from Course,Teacher,SC whereeacher.Tid and SCCid=course.Cid and Tname=' 叶平');
48、查询两门以上不及格课程的同学的**及其平均成绩

Course.Tid=T
group by Si
select Sid,avg(isnull(score,0) from SC where Sid in (selectSid from SC where score <60d having count(*)>2)group by Sid;

49、检索"4
课程分数小于60，按分数降序排列的同学**

select Sid from SC

where Cid='4'and score <60 order by score desc;

50、删除"2
同学的"1 课程的成绩

delete from Sc where Sid='1'and Cid='1';