sql面试题（学生表_课程表_成绩表_教师表）
21、查询不同老师所教不同课程平均分从高到低显示
SELECT max(#) AS 教师ID,MAX() AS 教师姓名,# AS 课程ＩＤ,MAX() AS 课程名称,AVG(Score) AS 平均成绩
FROM SC AS T,Course AS C ,Teacher AS Z
where #=# and #=#
GROUP BY #
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）
[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
# As 学生学号,
AS 学生姓名 ,
AS 企业管理,
AS 马克思,
AS UML,
AS 数据库,
ISNULL(,0) + ISNULL(,0) + ISNULL(,0) + ISNULL(,0) as 总分
FROM Student,SC LEFT JOIN SC AS T1
ON # = # AND # = '001'
LEFT JOIN SC AS T2
ON # = # AND # = '002'
LEFT JOIN SC AS T3
ON # = # AND # = '003'
LEFT JOIN SC AS T4
ON # = # AND # = '004'
WHERE #=# and
ISNULL(,0) + ISNULL(,0) + ISNULL(,0) + ISNULL(,0)
NOT IN
(SELECT
DISTINCT
TOP 15 WITH TIES
ISNULL(,0) + ISNULL(,0) + ISNULL(,0) + ISNULL(,0)
FROM sc
LEFT JOIN sc AS T1
ON # = # AND # = 'k1'
LEFT JOIN sc AS T2
ON # = # AND # = 'k2'
LEFT JOIN sc AS T3
ON # = # AND # = 'k3'
LEFT JOIN sc AS T4
ON # = # AND # = 'k4'
ORDER BY ISNULL(,0) + ISNULL(,0) + ISNULL(,0) + ISNULL(,0) DESC);
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 # 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 #=#
GROUP BY #,Cname;
24、查询学生平均成绩及其名次
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 # as 学生ID,# as 课程ID,Score as 分数
FROM SC t1
WHERE score IN (SELECT TOP 3 score
FROM SC
WHERE #= C#
ORDER BY score DESC
)
ORDER BY #;
26、查询每门课程被选修的学生数
select c#,count(S#) from sc group by C#;
27、查询出只选修了一门课程的全部学生的学号和姓名
select #,,count(C#) AS 选课数
from SC ,Student
where #=# group by # , 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='男';
Select count(Ssex) as 女生人数 from Student group by Ssex having Ssex='女'；
29、查询姓“张”的学生名单
SELECT Sname FROM Student WHERE Sname like '张%';
30、查询同名同性学生名单，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 C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ;
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 Sname,# ,avg(score)
from Student,SC
where #=# group by #,Sname having avg(score)>85;
34、查询课程名称为“数据库”，且分数低于60的学生姓名和分数
Select Sname,isnull(score,0)
from Student,SC,Course
where #=# and #=# and ='数据库'and score <60;
35、查询所有学生的选课情况；
SELECT #,#,Sname,Cname
FROM SC,Student,Course
where #=# and #=# ;
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 #,,#,
FROM student,Sc
WHERE >=70 AND #=#;
37、查询不及格的课程，并按课程号从大到小排列
select c# from sc where scor e <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 #, from SC,Student where #=# 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 ,score
from Student,SC,Course C,Teacher
where #=# and #=# and #=# and ='叶平' and =(select max(score)from SC where 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的学号、课程号、学生成绩
select distinct #, from SC A ,SC B where = and # <># ;
43、查询每门功成绩最好的前两名
SELECT # as 学生ID,# as 课程ID,Score as 分数
FROM SC t1
WHERE score IN (SELECT TOP 2 score
FROM SC
WHERE #= C#
ORDER BY score DESC
)
ORDER BY #;
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 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、查询全部学生都选修的课程的课程号和课程名
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 #=# and #=# and Tname='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 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
delete from Sc where S#='001'and C#='001';