sql面试题1 学生成绩_SQL

sql面试题一学生成绩

sql面试题一学生成绩

原帖链接:http://topic.csdn.net/u/20081020/15/1ABF54D0-F401-42AB-A75E-DF90027CEBA0.html

表架构

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

建表语句?

CREATETABLE student

? (

???? s#???INT,

???? sname nvarchar(32),

???? sage?INT,

???? ssex?nvarchar(8)

? )

CREATETABLE course

? (

???? c#???INT,

???? cname nvarchar(32),

???? t#???INT

? )

CREATETABLE sc

? (

???? s#???INT,

???? c#???INT,

???? score INT

? )

CREATETABLE teacher

? (

???? t#???INT,

???? tname nvarchar(16)

? )

插入测试数据语句?

insertinto Student select1,N'刘一',18,N'男'unionall

?select2,N'钱二',19,N'女'unionall

?select3,N'张三',17,N'男'unionall

?select4,N'李四',18,N'女'unionall

?select5,N'王五',17,N'男'unionall

?select6,N'赵六',19,N'女'

?insertinto Teacher select1,N'叶平'unionall

?select2,N'贺高'unionall

?select3,N'杨艳'unionall

?select4,N'周磊'

?insertinto Course select1,N'语文',1unionall

?select2,N'数学',2unionall

?select3,N'英语',3unionall

?select4,N'物理',4

?insertinto SC

?select1,1,56unionall

?select1,2,78unionall

?select1,3,67unionall

?select1,4,58unionall

?select2,1,79unionall

?select2,2,81unionall

?select2,3,92unionall

?select2,4,68unionall

?select3,1,91unionall

?select3,2,47unionall

?select3,3,88unionall

?select3,4,56unionall

?select4,2,88unionall

?select4,3,90unionall

?select4,4,93unionall

?select5,1,46unionall

?select5,3,78unionall

?select5,4,53unionall

?select6,1,35unionall

?select6,2,68unionall

?select6,4,71

问题

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,(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

??? 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))

? from Teacher

? where Tname like'李%';

5、查询没学过“叶平”老师课的同学的学号、姓名；

??? select Student.S#,Student.Sname

??? from Student?

??? 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；

? 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'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；

? select S#,Sname

? from Student

? where S# notin (select S.S# from Student AS S,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# 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 distinct S#,Sname from Student,SCwhere?Student.S#=SC.S# and SC.C# in (select 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；

??? selectdistinct SC.S#,Sname

??? from Student,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)

??? 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“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

??? 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“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 AS t

??? GROUPBY S#

??? 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 AS R

??? WHERE L.C# = R.C# and

??????? L.score = (SELECTMAX(IL.score)

????????????????????? FROM SC AS IL,Student AS IM

????????????????????? WHERE L.C# = IL.C# and IM.S#=IL.S#

????????????????????? GROUPBY IL.C#)

??????? AND

??????? R.Score = (SELECTMIN(IR.score)

????????????????????? FROM SC AS IR

????????????? ????????WHERE R.C# = IR.C#

????????????????? GROUPBY IR.C#

??????????????????? );
自己写的:select c# ,max(score)as 最高分 ,min(score) as 最低分 from dbo.sc ?group by 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(CASEWHEN? isnull(score,0)>=60THEN1ELSE0END)/COUNT(*) AS及格百分数

??? FROM SC T,Course

??? where t.C#=course.C#

??? GROUPBY t.C#

??? ORDERBY100*SUM(CASEWHEN? isnull(score,0)>=60THEN1ELSE0END)/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（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马克平均分

??????? ,100*SUM(CASEWHEN C# ='002'AND score >=60THEN1ELSE0END)/SUM(CASEWHEN C# ='002'THEN1ELSE0END) AS马克及格百分数

??????? ,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 AS Z

??? where T.C#=C.C# and C.T#=Z.T#

? GROUPBY C.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（002），UML （003），数据库（004）

??? [学生ID],[学生姓名],企业管理,马克,UML,数据库,平均成绩

??? SELECT? DISTINCTtop3

????? 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,

????? 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? LEFTJOIN SC AS T1

????????????????????? ON SC.S# = T1.S# AND T1.C# ='001'

??????????? LEFTJOIN SC AS T2

????????????????????? ON SC.S# = T2.S# AND T2.C# ='002'

?? ?????????LEFTJOIN SC AS T3

????????????????????? ON SC.S# = T3.S# AND T3.C# ='003'

??????????? LEFTJOIN 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)

????? NOTIN

????? (SELECT

??????????? DISTINCT

??????????? TOP15WITH TIES

??????????? ISNULL(T1.score,0) +ISNULL(T2.score,0) +ISNULL(T3.score,0) +ISNULL(T4.score,0)

????? FROM sc

??????????? LEFTJOIN sc AS T1

????????????????????? ON sc.S# = T1.S# AND T1.C# ='k1'

??????????? LEFTJOIN sc AS T2

????????????????????? ON sc.S# = T2.S# AND T2.C# ='k2'

??????????? LEFTJOIN sc AS T3

????????????????????? ON sc.S# = T3.S# AND T3.C# ='k3'

????????? ??LEFTJOIN sc AS T4

????????????????????? 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,Course

??? where 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

????????????????????? FROM SC

????????????????? GROUPBY 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

??????? GROUPBY S#

??????? ) AS T2

??? 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

????? FROM SC t1

????? WHERE score IN (SELECTTOP3 score

????????????? FROM SC

????????????? 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

? from SC ,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 Student groupby 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 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)

??? from Student,SC

??? where Student.S#=SC.S# groupby SC.S#,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 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>=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

??? 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

??? 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

????? FROM SC t1

????? WHERE score IN (SELECTTOP2 score

????????????? FROM SC

????????????? 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

??? 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# 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';

问题描述：

本题用到下面三个关系表：

CARD 借书卡。 CNO 卡号，NAME 姓名，CLASS 班级

BOOKS 图书。 BNO 书号，BNAME 书名,AUTHOR 作者，PRICE 单价，QUANTITY 库存册数

BORROW 借书记录。 CNO 借书卡号，BNO 书号，RDATE 还书日期

备注：限定每人每种书只能借一本；库存册数随借书、还书而改变。

要求实现如下15个处理：

1. 写出建立BORROW表的SQL语句，要求定义主码完整性约束和引用完整性约束

--实现代码：

CREATETABLE BORROW(

??? CNO intFOREIGNKEYREFERENCES CARD(CNO),

??? BNO intFOREIGNKEYREFERENCES BOOKS(BNO),

??? RDATE datetime,

??? PRIMARYKEY(CNO,BNO))

2. 找出借书超过5本的读者,输出借书卡号及所借图书册数

--实现代码：

SELECT CNO,借图书册数=COUNT(*)

FROM BORROW

GROUPBY CNO

HAVINGCOUNT(*)>5

3. 查询借阅了"水浒"一书的读者，输出姓名及班级

--实现代码：

SELECT*FROM CARD c

WHEREEXISTS(

??? SELECT*FROM BORROW a,BOOKS b

??? WHERE a.BNO=b.BNO

??????? AND b.BNAME=N'水浒'

??????? AND a.CNO=c.CNO)

4. 查询过期未还图书，输出借阅者（卡号）、书号及还书日期

--实现代码：

SELECT*FROM BORROW

WHERE RDATE<GETDATE()

5. 查询书名包括"网络"关键词的图书，输出书号、书名、作者

--实现代码：

SELECT BNO,BNAME,AUTHOR FROM BOOKS

WHERE BNAME LIKE N'%网络%'

6. 查询现有图书中价格最高的图书，输出书名及作者

--实现代码：

SELECT BNO,BNAME,AUTHOR FROM BOOKS

WHERE PRICE=(

??? SELECTMAX(PRICE) FROM BOOKS)

7. 查询当前借了"计算方法"但没有借"计算方法习题集"的读者，输出其借书卡号，并按卡号降序排序输出

--实现代码：

SELECT a.CNO

FROM BORROW a,BOOKS b

WHERE a.BNO=b.BNO AND b.BNAME=N'计算方法'

??? ANDNOTEXISTS(

??????? SELECT*FROM BORROW aa,BOOKS bb

??????? WHERE aa.BNO=bb.BNO

??????????? AND bb.BNAME=N'计算方法习题集'

??????????? AND aa.CNO=a.CNO)

ORDERBY a.CNO DESC

8. 将"C01"班同学所借图书的还期都延长一周

--实现代码：

UPDATE b SET RDATE=DATEADD(Day,7,b.RDATE)

FROM CARD a,BORROW b

WHERE a.CNO=b.CNO

??? AND a.CLASS=N'C01'

9. 从BOOKS表中删除当前无人借阅的图书记录

--实现代码：

DELETE A FROM BOOKS a

WHERENOTEXISTS(

??? SELECT*FROM BORROW

??? WHERE BNO=a.BNO)

10. 如果经常按书名查询图书信息，请建立合适的索引

--实现代码：

CREATECLUSTEREDINDEX IDX_BOOKS_BNAME ON BOOKS(BNAME)

11. 在BORROW表上建立一个触发器，完成如下功能：如果读者借阅的书名是"数据库技术及应用"，就将该读者的借阅记录保存在BORROW_SAVE表中（注ORROW_SAVE表结构同BORROW表）

--实现代码：

CREATETRIGGER TR_SAVE ON BORROW

FORINSERT,UPDATE

IF@@ROWCOUNT>0

INSERT BORROW_SAVE SELECT i.*

FROM INSERTED i,BOOKS b

WHERE i.BNO=b.BNO

??? AND b.BNAME=N'数据库技术及应用'

12. 建立一个视图，显示"力01"班学生的借书信息（只要求显示姓名和书名）

--实现代码：

CREATEVIEW V_VIEW

SELECT a.NAME,b.BNAME

FROM BORROW ab,CARD a,BOOKS b

WHERE ab.CNO=a.CNO

??? AND ab.BNO=b.BNO

??? AND a.CLASS=N'力01'

13. 查询当前同时借有"计算方法"和"组合数学"两本书的读者，输出其借书卡号，并按卡号升序排序输出

--实现代码：

SELECT a.CNO

FROM BORROW a,BOOKS b

WHERE a.BNO=b.BNO

??? AND b.BNAME IN(N'计算方法',N'组合数学')

GROUPBY a.CNO

HAVINGCOUNT(*)=2

ORDERBY a.CNO DESC

14. 假定在建BOOKS表时没有定义主码，写出为BOOKS表追加定义主码的语句

--实现代码：

ALTERTABLE BOOKS ADDPRIMARYKEY(BNO)

15.1将NAME最大列宽增加到10个字符（假定原为6个字符）

--实现代码：

ALTERTABLE CARD ALTERCOLUMN NAME varchar(10)

15.2为该表增加1列NAME（系名），可变长，最大20个字符

--实现代码：

ALTERTABLE CARD ADD系名varchar(20)

问题描述：为管理岗位业务培训信息，建立3个表:

S (S#,SN,SD,SA) S#,SN,SD,SA 分别代表学号、学员姓名、所属单位、学员年龄

C (C#,CN ) C#,CN 分别代表课程编号、课程名称

SC ( S#,C#,G ) S#,C#,G 分别代表学号、所选修的课程编号、学习成绩

要求实现如下5个处理：

1. 使用标准SQL嵌套语句查询选修课程名称为’税收基础’的学员学号和姓名

--实现代码：

SELECT SN,SD FROM S

WHERE[S#]IN(

??? SELECT[S#]FROM C,SC

??? WHERE C.[C#]=SC.[C#]

??????? AND CN=N'税收基础')

2. 使用标准SQL嵌套语句查询选修课程编号为’C2’的学员姓名和所属单位

--实现代码：

SELECT S.SN,S.SD FROM S,SC

WHERE S.[S#]=SC.[S#]

??? AND SC.[C#]='C2'

3. 使用标准SQL嵌套语句查询不选修课程编号为’C5’的学员姓名和所属单位

--实现代码：

SELECT SN,SD FROM S

WHERE[S#]NOTIN(

??? SELECT[S#]FROM SC

??? WHERE[C#]='C5')

4. 使用标准SQL嵌套语句查询选修全部课程的学员姓名和所属单位

--实现代码：

SELECT SN,SD FROM S

WHERE[S#]IN(

??? SELECT[S#]FROM SC

??????? RIGHTJOIN C ON SC.[C#]=C.[C#]

??? GROUPBY[S#]

??? HAVINGCOUNT(*)=COUNT(DISTINCT[S#]))

5. 查询选修了课程的学员人数

--实现代码：

SELECT学员人数=COUNT(DISTINCT[S#]) FROM SC

6. 查询选修课程超过5门的学员学号和所属单位

--实现代码：

SELECT SN,SD FROM S

WHERE[S#]IN(

??? SELECT[S#]FROM SC

??? GROUPBY[S#]

??? HAVINGCOUNT(DISTINCT[C#])>5)