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“001”课程比“002”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,(selects#,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)
fromsc
groupby S# havingavg(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 leftOuterjoin SC on Student.S#=SC.S#
groupby Student.S#,Sname
4、查询姓“李”的老师的个数；
selectcount(distinct(Tname))
fromTeacher
where Tname like'李%';
5、查询没学过“叶平”老师课的同学的学号、姓名；
Student.S#,Student.Sname
fromStudent
where S# notin (selectdistinct( 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“001”并且也学过编号“002”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'andexists( Select*from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#='002');
7、查询学过“叶平”老师所教的所有课的同学的学号、姓名；
selectS#,Sname
fromStudent
where S# in (select S# from SC ,Course ,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='叶平'groupby S# havingcount(SC.C#)=(selectcount(C#) from
Course,Teacher where Teacher.T#=Course.T# and Tname='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 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；
selectS#,Sname
fromStudent
where S# notin (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；
selectStudent.S#,Student.Sname
fromStudent,SC
where Student.S#=SC.S# groupby Student.S#,Student.Sname havingcount(C#) <(selectcount(C#) 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 S#,Sname from Student,SC where Student.S#=SC.S# and C# inselect C# from SC where S#='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；
selectdistinctSC.S#,Sname
fromStudent,SC
where Student.S#=SC.S# and C# in (select C# from SC where S#='001');
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；
update SC set score=(selectavg(SC_2.score)
fromSC 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“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 S# from SC where C# in (select C# from SC where S#='1002')
groupby
S# havingcount(*)=(selectcount(*) from SC where S#='1002');
15、删除学习“叶平”老师课的SC表记录；
Delect SC
fromcourse ,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“003”课程的同学学号、2、
号课的平均成绩；
Insert SC select S#,'002',(Selectavg(score)
from SC where C#='002') from Student where S# notin (Select S# from SC where C#='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 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 ASt
GROUPBYS#
ORDERBYavg(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 ASR
WHERE L.C# = R.C# and
L.score = (SELECTMAX(IL.score)
FROM SC AS IL,Student ASIM
WHERE L.C# = IL.C# and IM.S#=IL.S#
GROUPBYIL.C#)
AND
R.Score
= (SELECTMIN(IR.score)
FROM SC ASIR
WHERE R.C# =IR.C#
GROUPBYIR.C#
);
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.C# AS课程号,max(course.Cname)AS课程名,isnull(AVG(score),0) AS平均成绩
,100*SUM(CASEWHENisnull(score,0)>=60THEN1ELSE0END)/COUNT(*) AS及格百分数
FROMSC T,Course
where t.C#=course.C#
GROUPBYt.C#
ORDERBY100*SUM(CASEWHENisnull(score,0)>=60THEN1ELSE
0END)/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）
SELECTSUM(CASEWHEN C# ='001'THEN score ELSE0END)/SUM(CASE C# WHEN'001'THEN1ELSE0END) AS企业管理平均分
,100*SUM(CASEWHEN C# ='001'AND score >=60THEN1ELSE0END)/SUM(CASEWHEN C# ='001'THEN1ELSE0END
) AS企业管理及格百分数
,SUM(CASEWHEN C# ='002'THEN score ELSE0END)/SUM(CASE C# WHEN'002'THEN1ELSE0END) AS马克思平均分
,100*SUM(CASEWHEN C# ='002'AND score >=60THEN1ELSE0END)/SUM(CASEWHEN C# ='002'THEN1ELSE0END) AS马克思及格百分数
,SUM(CASEWHEN C# ='003'THEN score ELSE0END)/
SUM(CASE C# WHEN'003'THEN1ELSE0END) AS UML平均分
,100*SUM(CASEWHEN C# ='003'AND score >=60THEN1ELSE0END)/SUM(CASEWHEN C# ='003'THEN1ELSE0END) AS UML及格百分数
,SUM(CASEWHEN C# ='004'THEN score ELSE0END)/SUM(CASE C# WHEN'004'THEN1ELSE0END) AS数据库平均分
,100
*SUM(CASEWHEN C# ='004'AND score >=60THEN1ELSE0END)/SUM(CASEWHEN C# ='004'THEN1ELSE0END) AS数据库及格百分数
FROM SC
21、查询不同老师所教不同课程平均分从高到低显示
SELECTmax(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 ASZ
where T.C#=C.C# and C.T#=Z.T#
GROUPBYC.C#
ORDERBYAVG(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
SELECTDISTINCTtop3
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
ASUML,
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 LEFTJOIN SC AST1
ON SC.S# = T1.S# AND T1.C# ='001'
LEFTJOIN SC AST2
ON SC.S# = T2.S# AND T2.C# ='002'
LEFTJOIN SC AST3
ON SC.S# =T3.S# AND T3.C# ='003'
LEFTJOIN SC AST4
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)
NOTIN
(SELECT
DISTINCT
TOP15WITHTIES
ISNULL(T1.score,0) +ISNULL(T2.score,0) +ISNULL(T3.score,0) +ISNULL(T4.score,0)
FROMsc
LEFTJOIN sc AST1
ON sc.S# = T1.S# AND T1.C#='k1'
LEFTJOIN sc AST2
ON sc.S# = T2.S# AND T2.C# ='k2'
LEFTJOIN sc AST3
ON sc.S# = T3.S# AND T3.C# ='k3'
LEFTJOIN sc AST4
ON sc.S# = T4.S# AND T4.C# ='k4'
ORDERBYISNULL(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(CASEWHEN score BETWEEN85AND100THEN1ELSE0END) AS[100 - 85]
,SUM(CASEWHEN score BETWEEN70AND85THEN1ELSE0END) AS[85 - 70]
,SUM(CASEWHEN score BETWEEN60AND70THEN1ELSE0END) AS[70 - 60]
,SUM(CASEWHEN score <60THEN1ELSE0END) AS[60 -]
FROM SC,Coursewhere SC.C#=Course.C#
GROUPBY SC.C#,Cname;
24、查询学生平均成绩及其名次
SELECT1+(SELECTCOUNT( distinct平均成绩)
FROM (SELECT S#,AVG(score) AS平均成绩
FROMSC
GROUPBYS#
)
AST1
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
FROMSC
GROUPBYS#
)
AST2
ORDERBY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
FROMSC t1
WHERE score IN (SELECTTOP3score
FROMSC
WHERE t1.C#= C#ORDERBY score DESC
)
ORDERBY t1.C#;
26、查询每门课程被选修的学生数
select c#,count(S#) from sc groupby 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
where SC.S#=Student.S# groupby SC.S# ,Student.Sname havingcount(C#)=1;
28、查询男生、女生人数
Selectcount(Ssex) as男生人数from Student groupby Ssex having Ssex='男';
Selectcount(Ssex) as女生人数from Student groupby 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 Studentgroupby Sname havingcount(*)>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)) asage
fromstudent
whereCONVERT(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 groupby C# orderbyAvg(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)
fromStudent,SC
where Student.S#=SC.S# groupby SC.S#,Sname havingavg(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)
fromStudent,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；
SELECTSC.S#,SC.C#,Sname,Cname
FROMSC,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；
SELECTdistinctstudent.S#,student.Sname,SC.C#,SC.score
FROMstudent,Sc
WHERE SC.score>=70AND 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 <60orderby 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>80and C#='003';
39、求选了课程的学生人数
selectcount(*) 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
selectStudent.Sname,score
fromStudent,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
selectcount(*) from sc groupby 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
selectdistinct 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
FROMSC t1
WHERE score IN (SELECTTOP2score
FROMSC
WHERE t1.C#=C#
ORDERBY score DESC
)
ORDERBY 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
fromsc
groupbyC#
orderbycount(*) desc,c#
45、检索至少选修两门课程的学生学号
selectS#
fromsc
groupbys#
havingcount(*) >=2
46、查询全部学生都选修的课程的课程号和课程名
selectC#,Cname
fromCourse
where C# in (select c# from sc groupby 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# notin (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 <60groupby S# havingcount(*)>2)groupby 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 <60orderby score desc;
50、删除“002”同学的“001”课程的成绩
deletefrom Sc where S#='001'and C#='001';
