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 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
)
ORDER BY t1.C#;
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 SC.S#,Student.Sname,count(C#) AS选课数
FROMSC ,Student
WHERESC.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 StudentGROUP BY Ssex having Ssex='男';
SELECT count(Ssex) as 女生人数FROM StudentGROUP 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、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;
34、查询课程名称为“数据库”，且分数低于的学生姓名和分数
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排列
SELECT c# FROM sc WHERE scor e <60 ORDER BY C# ;
38、查询课程编号为且课程成绩在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# ANDScore>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=(SELECTmax(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的学号、课程号、学生成绩
SELECT distinct A.S#,B.score FROM SC A ,SC B WHERE A.Score=B.ScoreAND A.C# <>B.C# ;
43、查询每门功成绩最好的前两名
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 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,SCWHERE 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及其平均成绩
SELECT S#,avg(isnull(score,0)) FROM SC WHERE S# in (SELECT S# FROM SC WHEREscore <60 GROUP BY S# having count(*)>2)GROUP BY S#;