SQL数据库面试题以及答案

Student(stuId,stuName,stuAge,stuSex)学生表 stuId：学号；stuName：学生姓名；stuAge：学生年龄；stuSex：学生性别 Course(courseId,courseName,teacherId)课程表 courseId,课程编号；courseName：课程名字；teacherId：教师编号 Scores(stuId,courseId,sc

Student(stuId,stuName,stuAge,stuSex) 学生表

stuId：学号；stuName：学生姓名；stuAge：学生年龄；stuSex：学生性别

Course(courseId,courseName,teacherId) 课程表

courseId,课程编号；courseName：课程名字；teacherId：教师编号

Scores(stuId,courseId,score) 成绩表

stuId：学号；courseId,课程编号；score：成绩

Teacher(teacherId,teacherName) 教师表

teacherId：教师编号； teacherName：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.stuId from (select stuId,score from Scores where courseId='001') a,(select stuId,score

from Scores where courseId='002') b

where a.score>b.score and a.stuId=b.stuId;

2、查询平均成绩大于60分的同学的学号和平均成绩；

select stuId,avg(score)

from Scores

group by stuId having avg(score) >60;

3、查询所有同学的学号、姓名、选课数、总成绩；

select Student.stuId,Student.stuName,count(Scores.courseId),sum(score)

from Student left Outer join Scores on Student.stuId=Scores.stuId

group by Student.stuId,stuName

4、查询姓“李”的老师的个数；

select count(distinct(teacherName))

from Teacher

where teacherName like '李%';

5、查询没学过“叶平”老师课的同学的学号、姓名；

select Student.stuId,Student.stuName

from Student

where stuId not in (select distinct( Scores.stuId) from Scores,Course,Teacher where Scores.courseId=Course.courseId and Teacher.teacherId=Course.teacherId and Teacher.teacherName='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.stuId,Student.stuName from Student,Scores where Student.stuId=Scores.stuId and Scores.courseId='001'and exists( Select * from Scores as Scores_2 where Scores_2.stuId=Scores.stuId and Scores_2.courseId='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 stuId,stuName

from Student

where stuId in (select stuId from Scores ,Course ,Teacher where Scores.courseId=Course.courseId and Teacher.teacherId=Course.teacherId and Teacher.teacherName='叶平' group by stuId having count(Scores.courseId)=(select count(courseId) from Course,Teacher where Teacher.teacherId=Course.teacherId and teacherName='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 stuId,stuName from (select Student.stuId,Student.stuName,score ,(select score from Scores Scores_2 where Scores_2.stuId=Student.stuId and Scores_2.courseId='002') score2

from Student,Scores where Student.stuId=Scores.stuId and courseId='001') S_2 where score2

9、查询所有课程成绩小于60分的同学的学号、姓名；

select stuId,stuName

from Student

where stuId not in (select Student.stuId from Student,Scores where S.stuId=Scores.stuId and score>60);

10、查询没有学全所有课的同学的学号、姓名；

select Student.stuId,Student.stuName

from Student,Scores

where Student.stuId=Scores.stuId group by Student.stuId,Student.stuName having count(courseId) <(select count(courseId) 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；

select stuId,stuName from Student,Scores where Student.stuId=Scores.stuId and courseId in select courseId from Scores where stuId='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；

select distinct Scores.stuId,stuName

from Student,Scores

where Student.stuId=Scores.stuId and courseId in (select courseId from Scores where stuId='001');

13、把“Scores”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 Scores set score=(select avg(Scores_2.score)

from Scores Scores_2

where Scores_2.courseId=Scores.courseId ) from Course,Teacher where Course.courseId=Scores.courseId and Course.teacherId=Teacher.teacherId and Teacher.teacherName='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 stuId from Scores where courseId in (select courseId from Scores where stuId='1002')

group by stuId having count(*)=(select count(*) from Scores where stuId='1002');

15、删除学习“叶平”老师课的Scores表记录；

Delect Scores

from course ,Teacher

where Course.courseId=Scores.courseId and Course.teacherId= Teacher.teacherId and teacherName='叶平';

16、向Scores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 Scores select stuId,'002',(Select avg(score)

from Scores where courseId='002') from Student where stuId not in (Select stuId from Scores where courseId='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 stuId as 学生ID

,(SELECT score FROM Scores WHERE Scores.stuId=t.stuId AND courseId='004') AS 数据库

,(SELECT score FROM Scores WHERE Scores.stuId=t.stuId AND courseId='001') AS 企业管理

,(SELECT score FROM Scores WHERE Scores.stuId=t.stuId AND courseId='006') AS 英语

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

FROM Scores AS t

GROUP BY stuId

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.courseId As 课程ID,L.score AS 最高分,R.score AS 最低分

FROM Scores L ,Scores AS R

WHERE L.courseId = R.courseId and

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

FROM Scores AS IL,Student AS IM

WHERE L.courseId = IL.courseId and IM.stuId=IL.stuId

GROUP BY IL.courseId)

AND

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

FROM Scores AS IR

WHERE R.courseId = IR.courseId

GROUP BY IR.courseId

);

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.courseId AS 课程号,max(course.courseName)AS 课程名,isnull(AVG(score),0) AS 平均成绩

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

FROM Scores T,Course

where t.courseId=course.courseId

GROUP BY t.courseId

ORDER BY 100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DEScores

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 courseId ='001' THEN score ELSE 0 END)/SUM(CASE courseId WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分

,100 * SUM(CASE WHEN courseId = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN courseId = '001' THEN 1 ELSE 0 END) AS 企业管理及格百分数

,SUM(CASE WHEN courseId = '002' THEN score ELSE 0 END)/SUM(CASE courseId WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分

,100 * SUM(CASE WHEN courseId = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN courseId = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数

,SUM(CASE WHEN courseId = '003' THEN score ELSE 0 END)/SUM(CASE courseId WHEN '003' THEN 1 ELSE 0 END) AS UML平均分

,100 * SUM(CASE WHEN courseId = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN courseId = '003' THEN 1 ELSE 0 END) AS UML及格百分数

,SUM(CASE WHEN courseId = '004' THEN score ELSE 0 END)/SUM(CASE courseId WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分

,100 * SUM(CASE WHEN courseId = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN courseId = '004' THEN 1 ELSE 0 END) AS 数据库及格百分数

FROM Scores

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.teacherId) AS 教师ID,MAX(Z.teacherName) AS 教师姓名,C.courseId AS 课程ＩＤ,MAX(C.courseName) AS 课程名称,AVG(score) AS 平均成绩

FROM Scores AS T,Course AS C ,Teacher AS Z

where T.courseId=C.courseId and C.teacherId=Z.teacherId

GROUP BY C.courseId

ORDER BY AVG(score) DEScores

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

Scores.stuId As 学生学号,

Student.stuName 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,Scores LEFT JOIN Scores AS T1

ON Scores.stuId = T1.stuId AND T1.courseId = '001'

LEFT JOIN Scores AS T2

ON Scores.stuId = T2.stuId AND T2.courseId = '002'

LEFT JOIN Scores AS T3

ON Scores.stuId = T3.stuId AND T3.courseId = '003'

LEFT JOIN Scores AS T4

ON Scores.stuId = T4.stuId AND T4.courseId = '004'

WHERE student.stuId=Scores.stuId 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 Scores

LEFT JOIN Scores AS T1

ON Scores.stuId = T1.stuId AND T1.courseId = 'k1'

LEFT JOIN Scores AS T2

ON Scores.stuId = T2.stuId AND T2.courseId = 'k2'

LEFT JOIN Scores AS T3

ON Scores.stuId = T3.stuId AND T3.courseId = 'k3'

LEFT JOIN Scores AS T4

ON Scores.stuId = T4.stuId AND T4.courseId = 'k4'

ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DEScores);

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 Scores.courseId as 课程ID, courseName 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 -]

FROM Scores,Course

where Scores.courseId=Course.courseId

GROUP BY Scores.courseId,courseName;

24、查询学生平均成绩及其名次

SELECT 1+(SELECT COUNT( distinct 平均成绩)

FROM (SELECT stuId,AVG(score) AS 平均成绩

FROM Scores

GROUP BY stuId

) AS T1

WHERE 平均成绩 > T2.平均成绩) as 名次,

stuId as 学生学号,平均成绩

FROM (SELECT stuId,AVG(score) 平均成绩

FROM Scores

GROUP BY stuId

) AS T2

ORDER BY 平均成绩 deScores;

25、查询各科成绩前三名的记录:(不考虑成绩并列情况)

SELECT t1.stuId as 学生ID,t1.courseId as 课程ID,score as 分数

FROM Scores t1

WHERE score IN (SELECT TOP 3 score

FROM Scores

WHERE t1.courseId= courseId

ORDER BY score DEScores

)

ORDER BY t1.courseId;

26、查询每门课程被选修的学生数

select courseId,count(stuId) from Scores group by courseId;

27、查询出只选修了一门课程的全部学生的学号和姓名

select Scores.stuId,Student.stuName,count(courseId) AS 选课数

from Scores ,Student

where Scores.stuId=Student.stuId group by Scores.stuId ,Student.stuName having count(courseId)=1;

28、查询男生、女生人数

Select count(stuSex) as 男生人数 from Student group by stuSex having stuSex='男';

Select count(stuSex) as 女生人数 from Student group by stuSex having stuSex='女'；

29、查询姓“张”的学生名单

SELECT stuName FROM Student WHERE stuName like '张%';

30、查询同名同性学生名单，并统计同名人数

select stuName,count(*) from Student group by stuName having count(*)>1;;

31、1981年出生的学生名单(注：Student表中stuAge列的类型是datetime)

select stuName, CONVERT(char (11),DATEPART(year,stuAge)) as age

from student

where CONVERT(char(11),DATEPART(year,stuAge))='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

Select courseId,Avg(score) from Scores group by courseId order by Avg(score),courseId DEScores ;

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 stuName,Scores.stuId ,avg(score)

from Student,Scores

where Student.stuId=Scores.stuId group by Scores.stuId,stuName having avg(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

Select stuName,isnull(score,0)

from Student,Scores,Course

where Scores.stuId=Student.stuId and Scores.courseId=Course.courseId and Course.courseName='数据库'and score <60;

35、查询所有学生的选课情况；

SELECT Scores.stuId,Scores.courseId,stuName,courseName

FROM Scores,Student,Course

where Scores.stuId=Student.stuId and Scores.courseId=Course.courseId ;

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 distinct student.stuId,student.stuName,Scores.courseId,Scores.score

FROM student,Scores

WHERE Scores.score>=70 AND Scores.stuId=student.stuId;

37、查询不及格的课程，并按课程号从大到小排列

select courseId from Scores where Scoresor e <60 order by courseId ;

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 Scores.stuId,Student.stuName from Scores,Student where Scores.stuId=Student.stuId and score>80 and courseId='003';

39、求选了课程的学生人数

select count(*) from Scores;

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 Student.stuName,score

from Student,Scores,Course C,Teacher

where Student.stuId=Scores.stuId and Scores.courseId=C.courseId and C.teacherId=Teacher.teacherId and Teacher.teacherName='叶平' and Scores.score=(select max(score)from Scores where courseId=C.courseId );

41、查询各个课程及相应的选修人数

select count(*) from Scores group by courseId;

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.stuId,B.score from Scores A ,Scores B where A.score=B.score and A.courseId <>B.courseId ;

43、查询每门功成绩最好的前两名

SELECT t1.stuId as 学生ID,t1.courseId as 课程ID,score as 分数

FROM Scores t1

WHERE score IN (SELECT TOP 2 score

FROM Scores

WHERE t1.courseId= courseId

ORDER BY score DEScores

)

ORDER BY t1.courseId;

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 courseId as 课程号,count(*) as 人数

from Scores

group by courseId

order by count(*) deScores,courseId

45、检索至少选修两门课程的学生学号

select stuId

from Scores

group by stuId

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 courseId,courseName

from Course

where courseId in (select courseId from Scores group by courseId)

47、查询没学过“叶平”老师讲授的任一门课程的学生姓名

select stuName from Student where stuId not in (select stuId from Course,Teacher,Scores where Course.teacherId=Teacher.teacherId and Scores.courseId=course.courseId and teacherName='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

select stuId,avg(isnull(score,0)) from Scores where stuId in (select stuId from Scores where score <60 group by stuId having count(*)>2)group by stuId;

49、检索“004”课程分数小于60，按分数降序排列的同学学号

select stuId from Scores where courseId='004'and score <60 order by score deScores;

50、删除“002”同学的“001”课程的成绩

delete from Scores where stuId='002'and courseId='001';