SQL数据库面试50题(转载)

SQL数据库面试题以及答案(50例题) 

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:课程名称

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

2、查询平均成绩大于60分的同学的学号和平均成绩 

3、查询所有同学的学号、姓名、选课数、总成绩

4、查询姓‘李’的老师的个数:

5、查询没有学过“叶平”老师可的同学的学号、姓名: 

6、查询学过“叶平”老师所教的所有课的同学的学号、姓名: 

7、查询学过“011”并且也学过编号“002”课程的同学的学号、姓名: 

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:

9、查询所有课程成绩小于60的同学的学号、姓名: 

10、查询没有学全所有课的同学的学号、姓名:

11、查询至少有一门课与学号为“1001”同学所学相同的同学的学号和姓名: 

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; 

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: 

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: 

15、删除学习“叶平”老师课的SC表记录: 

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、002号课的平均成绩: 

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:

18、查询各科成绩最高和最低的分: 以如下的形式显示:课程ID,最高分,最低分

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:  

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):

21、查询不同老师所教不同课程平均分从高到低显示:

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)

23、统计下列各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ 小于60]

24、查询学生平均成绩及其名次:

25、查询各科成绩前三名的记录(不考虑成绩并列情况):

26、查询每门课程被选修的学生数: 

27、查询出只选修一门课程的全部学生的学号和姓名: 

28、查询男生、女生人数:

29、查询姓“张”的学生名单:

30、查询同名同姓的学生名单,并统计同名人数:

311981年出生的学生名单(注:student表中sage列的类型是datetime:

32、查询平均成绩大于85的所有学生的学号、姓名和平均成绩:

33、查询每门课程的平均成绩,结果按平均成绩升序排序,平均成绩相同时,按课程号降序排列:

34、查询课程名称为“数据库”,且分数低于60的学生名字和分数:

35、查询所有学生的选课情况: 

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:

37、查询不及格的课程,并按课程号从大到小的排列:

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:

39、求选了课程的学生人数:

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:

41、查询各个课程及相应的选修人数:

42、查询不同课程成绩相同的学生和学号、课程号、学生成绩:

43、查询每门课程成绩最好的前两名:

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序,若人数相同,按课程号升序排序 

45、检索至少选修两门课程的学生学号: 

46、查询全部学生选修的课程和课程号和课程名:

47、查询没学过”叶平”老师讲授的任一门课程的学生姓名: 

48、查询两门以上不及格课程的同学的学号以及其平均成绩: 

49、检索“004”课程分数小于60,按分数降序排列的同学学号:

50、删除“002”同学的“001”课程的成绩:

 

答案:

 

 

 

1

 

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

 

select S#, avg(score) from sc group by S# having avg(score)>60

 

3

 

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

 

select count(distinct(Tname)) from teacher where tname like '%';

 

5

 

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 Teahcer.Tname ='叶平');

 

6

 

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='叶平' group by S#

 

having count(SC.C#)=(select count(C#) from Course,Teacher  

 

where Teacher.T#=Course.T# and Tname='叶平'));

 

7select 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');

 

8

 

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

 

select S#, sname

 

from student

 

where s# not in

 

(select student.s# from student, sc where s.s# = sc.s# and score>60);

 

10

 

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

 

select s#, Sname

 

from Student, SC

 

where student.s# = sc.s#

 

and c# in (select c# from SC where s#='1001');

 

12

 

select distinct sc.s# , sname

 

from student, sc

 

where student.s#=sc.s#

 

and c# in (select C# from sc where s#='001');

 

13

 

Update Sc Set Score=(Select Avg(s2_Score) From sc s2 Where s2.c#=sc.c#)  

 

Where c# IN

 

(Select c# From sc cs INNER JOIN Teacher tc ON cs.t#=tc.t# WHERE tname ='叶平')

 

14

 

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

 

delect sc

 

from course, Teacher

 

where course.c#=sc.c#

 

and course.t#=teacher.t#

 

and tname='叶平';

 

16

 

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

 

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 平局成绩

 

from sc as t

 

group by s#

 

order by avg(t.score)

 

18

 

select L.c# as 课程ID, L.score as 最高分,

 

R.score as 最低分

 

from sc L, sc R

 

where L.c# = R.c#

 

and L.score = (select max(IL.score)

 

        from sc 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

 

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

 

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):

 

21

 

 SELECT max(Z.T#) AS 教师ID,

 

 MAX(Z.Tname) AS 教师姓名,

 

 C.C# AS 课程ID,

 

 AVG(Score) AS 平均成绩     

 

 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)

 

23

 

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 -]     

 

FROM SC,Course     

 

where SC.C#=Course.C#     

 

GROUP BY SC.C#,Cname;

 

24

 

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 (SELECT S#,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)

 

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:

 

select count(Ssex) as 男生人数

 

from student

 

group by Ssex

 

having Ssex=''

 

select count(Ssex) as 女生人数

 

from student

 

group by Ssex

 

having Ssex='';

 

29、查询姓“张”的学生名单:

 

select sname

 

from student

 

where sname like '%';

 

30、查询同名同姓的学生名单,并统计同名人数:

 

select sanme,count(*)

 

from student

 

group by sname

 

havang count(*)>1; 

 

311981年出生的学生名单(注:student表中sage列的类型是datetime:

 

select sname, convert(char(11),DATEPART(year,sage)) as age

 

from student

 

where convert(char(11),DATEPART(year,Sage))='1981';

 

32、查询平均成绩大于85的所有学生的学号、姓名和平均成绩:

 

select Sname,SC.S# ,avg(score)     

 

from Student,SC      

 

where Student.S#=SC.S#

 

group by SC.S#,Sname

 

having    avg(score)>85;

 

33、查询每门课程的平均成绩,结果按平均成绩升序排序,平均成绩相同时,按课程号降序排列:

 

select C#, avg(score)

 

from sc

 

group by c#

 

order by avg(score), c# desc;

 

34、查询课程名称为“数据库”,且分数低于60的学生名字和分数:

 

select sname, isnull(score,0)

 

from student, sc ,course

 

where sc.s#=student.s#  and sc.c#=course.c# and course.cname='数据库' and score<60;

 

35、查询所有学生的选课情况:

 

select sc.s#,sc.c#,sname,cname

 

from sc,student course

 

where sc.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 distinct student.s#,student.sname,sc.c#,sc.score

 

from student,sc

 

where sc.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的排列:

 

select c#

 

from sc

 

where score<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:

 

select sc.s#,student.sname

 

from sc,student

 

where sc.s#=student.s# and score>80 and c#='003';

 

39、求选了课程的学生人数:

 

select count(*) 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:

 

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='叶平'

 

and sc.score=(select max(score) from sc where c#=c.c#);

 

41、查询各个课程及相应的选修人数: 

 

select count(*) from sc group by c#; 

 

42、查询不同课程成绩相同的学生和学号、课程号、学生成绩: 

 

select distinct a.s#,b.score

 

from sc a ,sc b

 

where a.score=b.score

 

and a.c#<>b.c#; 

 

43、查询每门课程成绩最好的前两名: 

 

select t1.s# as 学生ID,t1.c#  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序,若人数相同,按课程号升序排序: 

 

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、查询全部学生选修的课程和课程号和课程名: 

 

select c# ,cname

 

from course

 

where c# in (select c# from sc group by 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 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='叶平');

 

 48、查询两门以上不及格课程的同学的学号以及其平均成绩:

 

 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、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 score desc; 

 

50、删除“002”同学的“001”课程的成绩: 

 

delect from sc

 

where s#='002'

 

and c#='001';

 

posted on 2018-08-31 17:56  蓝色兔  阅读(1212)  评论(0编辑  收藏

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