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【MSSQL】 SQL50句
作者:Dezai.CN / 发布于2013/3/6/ 637
SQL50句

	Student(S#,Sname,Sage,Ssex) 学生表
	Course(C#,Cname,T#) 课程表
	SC(S#,C#,score) 成绩表
	Teacher(T#,Tname) 教师表

	问题：
	1、查询&ldquo;001&rdquo;课程比&ldquo;002&rdquo;课程成绩高的所有学生的学号；
	 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、查询平均成绩大于60分的同学的学号和平均成绩；
	 select S#,avg(score)
	 from sc
	 group by S# having avg(score) >60;

	3、查询所有同学的学号、姓名、选课数、总成绩；
	 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、查询姓&ldquo;李&rdquo;的老师的个数；
	 select count(distinct(Tname))
	 from Teacher
	 where Tname like '李%';

	5、查询没学过&ldquo;叶平&rdquo;老师课的同学的学号、姓名；
	 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 Teacher.Tname='叶平');

	6、查询学过&ldquo;001&rdquo;并且也学过编号&ldquo;002&rdquo;课程的同学的学号、姓名；
	 select 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');

	7、查询学过&ldquo;叶平&rdquo;老师所教的所有课的同学的学号、姓名；
	 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'));

	8、查询课程编号&ldquo;002&rdquo;的成绩比课程编号&ldquo;001&rdquo;课程低的所有同学的学号、姓名；
	 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、查询所有课程成绩小于60分的同学的学号、姓名；
	 select S#,Sname
	 from Student
	 where S# not in (select Student.S# from Student,SC where S.S#=SC.S# and score>60);

	10、查询没有学全所有课的同学的学号、姓名；
	 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、查询至少有一门课与学号为&ldquo;1001&rdquo;的同学所学相同的同学的学号和姓名；
	 select S#,Sname from Student,SC where Student.S#=SC.S# and C# in select C# from SC where S#='1001';

	12、查询至少学过学号为&ldquo;001&rdquo;同学所有一门课的其他同学学号和姓名；
	 select distinct SC.S#,Sname
	 from Student,SC
	 where Student.S#=SC.S# and C# in (select C# from SC where S#='001');

	13、把&ldquo;SC&rdquo;表中&ldquo;叶平&rdquo;老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.C#=SC.C# ) from Course,Teacher where Course.C#=SC.C# and Course.T#=Teacher.T# and Teacher.Tname='叶平');

	14、查询和&ldquo;1002&rdquo;号的同学学习的课程完全相同的其他同学学号和姓名；
	 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、删除学习&ldquo;叶平&rdquo;老师课的SC表记录；
	 Delect SC
	 from course ,Teacher
	 where Course.C#=SC.C# and Course.T#= Teacher.T# 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&ldquo;003&rdquo;课程的同学学号、2、
	 号课的平均成绩；
	 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、按平均成绩从高到低显示所有学生的&ldquo;数据库&rdquo;、&ldquo;企业管理&rdquo;、&ldquo;英语&rdquo;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 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 平均成绩
	 FROM SC AS t
	 GROUP BY S#
	 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.C# As 课程ID,L.score AS 最高分,R.score AS 最低分
	 FROM SC L ,SC AS R
	 WHERE L.C# = R.C# and
	 L.score = (SELECT MAX(IL.score)
	 FROM SC AS 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#
	 );

	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.T#) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.C# AS 课程ＩＤ,MAX(C.Cname) AS 课程名称,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）
	 [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
	 SC.S# As 学生学号,
	 Student.Sname 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,SC LEFT JOIN SC AS T1
	 ON SC.S# = T1.S# AND T1.C# = '001'
	 LEFT JOIN SC AS T2
	 ON SC.S# = T2.S# AND T2.C# = '002'
	 LEFT JOIN SC AS T3
	 ON SC.S# = T3.S# AND T3.C# = '003'
	 LEFT JOIN SC AS T4
	 ON SC.S# = T4.S# AND T4.C# = '004'
	 WHERE student.S#=SC.S# 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.S# = T1.S# AND T1.C# = 'k1'
	 LEFT JOIN sc AS T2
	 ON sc.S# = T2.S# AND T2.C# = 'k2'
	 LEFT JOIN sc AS T3
	 ON sc.S# = T3.S# AND T3.C# = 'k3'
	 LEFT JOIN sc AS T4
	 ON sc.S# = T4.S# AND T4.C# = 'k4'
	 ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,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 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、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
	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='男';
	 Select count(Ssex) as 女生人数 from Student group by Ssex having Ssex='女'；

	29、查询姓&ldquo;张&rdquo;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,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&ldquo;数据库&rdquo;，且分数低于60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 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&ldquo;叶平&rdquo;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.Score and 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&ldquo;叶平&rdquo;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&ldquo;004&rdquo;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&ldquo;002&rdquo;同学的&ldquo;001&rdquo;课程的成绩
	delete from Sc where S#='001'and C#='001';
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