??xml version="1.0" encoding="utf-8" standalone="yes"?>中文字幕一区二区三区乱码 ,狠狠色丁香久久综合频道,久久精品国产清自在天天线http://www.aygfsteel.com/wshao/category/54093.htmlzh-cnTue, 31 Dec 2013 07:22:36 GMTTue, 31 Dec 2013 07:22:36 GMT60T-SQL l典例题http://www.aygfsteel.com/wshao/archive/2013/12/31/408293.html午后星期?/dc:creator>午后星期?/author>Tue, 31 Dec 2013 06:37:00 GMThttp://www.aygfsteel.com/wshao/archive/2013/12/31/408293.htmlhttp://www.aygfsteel.com/wshao/comments/408293.htmlhttp://www.aygfsteel.com/wshao/archive/2013/12/31/408293.html#Feedback0http://www.aygfsteel.com/wshao/comments/commentRss/408293.htmlhttp://www.aygfsteel.com/wshao/services/trackbacks/408293.html有三张表Q?/span>

Student(S#,Sname,Sage,Ssex) 学生?br />Course(C#,Cname,T#) 评?br />SC(S#,C#,score) 成W?br />Teacher(T#,Tname) 教师?/span>

问题Q?br />1、查?#8220;001”评?#8220;002”评成W高的所有学生的学号Q?br />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^均成l大?0分的同学的学号和q_成WQ?br />    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、Ll；
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“?#8221;的老师的个敎ͼ
select count(distinct(Tname))
from Teacher
where Tname like '?';
5、查询没学过“叶^”老师评同学的学受姓名；
    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^');
6、查询学q?#8220;001”q且也学q编?#8220;002”评的同学的学号、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q?#8220;叶^”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^' group by S# having count(SC.C#)=(select count(C#) from Course,Teacher where Teacher.T#=Course.T# and Tname='叶^'));
8、查询课E编?#8220;002”的成l比评~号“001”评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E成l小?0分的同学的学受姓名；
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、查询至有一门课与学号ؓ“1001”的同学所学相同的同学的学号和姓名Q?br />    select S#,Sname from Student,SC where Student.S#=SC.S# and C# in select C# from SC where S#='1001';
12、查询至学q学号ؓ“001”同学所有一门课的其他同学学号和姓名Q?br />    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“SC”表中“叶^”老师教的评成W都更改ؓ此课E的q_成WQ?br />    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^');
14、查询和“1002”L同学学习的课E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?#8220;叶^”老师评SC表记录；
    Delect SC
    from course ,Teacher
    where Course.C#=SC.C# and Course.T#= Teacher.T# and Tname='叶^';
16、向SC表中插入一些记录，q些记录要求W合以下条gQ没有上q编?#8220;003”评的同学学受??br />    可的^均成l；
    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q_成W从高C昄所有学生的“数据?#8221;?#8220;企业理”?#8220;p”三门的课E成l，按如下Ş式显C：学生ID,,数据?企业理,p,有效评?有效q_?br />    SELECT S# as 学生ID
        ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='004') AS 数据?br />        ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='001') AS 企业理
        ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='006') AS p
        ,COUNT(*) AS 有效评? AVG(t.score) AS q_成W
    FROM SC AS t
    GROUP BY S#
    ORDER BY avg(t.score)
18、查询各U成l最高和最低的分：以如下Ş式显C：评IDQ最高分Q最低分
    SELECT L.C# As 评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#
                    );
19、按各科q_成W从低到高和及格率的百分数从高C序
    SELECT t.C# AS 评?max(course.Cname)AS 评?isnull(AVG(score),0) AS q_成W
        ,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格癑ֈ?br />    FROM SC T,Course
    where t.C#=course.C#
    GROUP BY t.C#
    ORDER BY 100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC
20、查询如下课E^均成l和及格率的癑ֈ??1?昄): 企业理Q?01Q，马克思（002Q，OO&UML Q?03Q，数据库（004Q?br />    SELECT SUM(CASE WHEN C# ='001' THEN score ELSE 0 END)/SUM(CASE C# WHEN '001' THEN 1 ELSE 0 END) AS 企业理q_?br />        ,100 * SUM(CASE WHEN C# = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '001' THEN 1 ELSE 0 END) AS 企业理及格癑ֈ?br />        ,SUM(CASE WHEN C# = '002' THEN score ELSE 0 END)/SUM(CASE C# WHEN '002' THEN 1 ELSE 0 END) AS 马克思^均分
        ,100 * SUM(CASE WHEN C# = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数
        ,SUM(CASE WHEN C# = '003' THEN score ELSE 0 END)/SUM(CASE C# WHEN '003' THEN 1 ELSE 0 END) AS UMLq_?br />        ,100 * SUM(CASE WHEN C# = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '003' THEN 1 ELSE 0 END) AS UML及格癑ֈ?br />        ,SUM(CASE WHEN C# = '004' THEN score ELSE 0 END)/SUM(CASE C# WHEN '004' THEN 1 ELSE 0 END) AS 数据库^均分
        ,100 * SUM(CASE WHEN C# = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '004' THEN 1 ELSE 0 END) AS 数据库及格百分数
FROM SC

21、查询不同老师所教不同课E^均分从高C昄
SELECT max(Z.T#) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.C# AS 评QＤ,MAX(C.Cname) AS 评名称,AVG(Score) AS q_成W
    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E成l第 3 名到W?6 名的学生成W单：企业理Q?01Q，马克思（002Q，UML Q?03Q，数据库（004Q?br />    [学生ID],[学生姓名],企业理,马克?UML,数据?q_成W
    SELECT DISTINCT top 3
      SC.S# As 学生学号,
        Student.Sname AS 学生姓名 ,
      T1.score AS 企业理,
      T2.score AS 马克?
      T3.score AS UML,
      T4.score AS 数据?
      ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as d
      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U成l?各分数段人数:评ID,评名称,[100-85],[85-70],[70-60],[ <60]
    SELECT SC.C# as 评ID, Cname as 评名称
        ,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^均成l及其名?br />      SELECT 1+(SELECT COUNT( distinct q_成W)
              FROM (SELECT S#,AVG(score) AS q_成W
                      FROM SC
                  GROUP BY S#
                  ) AS T1
            WHERE q_成W > T2.q_成W) as 名次,
      S# as 学生学号,q_成W
    FROM (SELECT S#,AVG(score) q_成W
            FROM SC
        GROUP BY S#
        ) AS T2
    ORDER BY q_成W desc;

25、查询各U成l前三名的记?(不考虑成Wq列情况)
      SELECT t1.S# as 学生ID,t1.C# as 评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E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E的全部学生的学号和姓名
select SC.S#,Student.Sname,count(C#) AS 选课?br />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h?br />    Select count(Ssex) as L人数 from Student group by Ssex having Ssex='?;
    Select count(Ssex) as 女生人数 from Student group by Ssex having Ssex='?Q?br />29、查询姓“?#8221;的学生名?br />    SELECT Sname FROM Student WHERE Sname like '?';
30、查询同名同性学生名单，q统计同名h?br />select Sname,count(*) from Student group by Sname having count(*)>1;;
31?981q出生的学生名单(注：Student表中Sage列的cd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E的q_成WQ结果按q_成W升序排列Q^均成l相同时Q按评号降序排?br />    Select C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ;
33、查询^均成l大?5的所有学生的学号、姓名和q_成W
    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E名UCؓ“数据?#8221;Q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?and score <60;
35、查询所有学生的选课情况Q?br />    SELECT SC.S#,SC.C#,Sname,Cname
    FROM SC,Student,Course
    where SC.S#=Student.S# and SC.C#=Course.C# ;
36、查询Q何一门课E成l在70分以上的姓名、课E名U和分数Q?br />    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E，q按评号从大到排?br />    select c# from sc where scor e <60 order by C# ;
38、查询课E编号ؓ003且课E成l在80分以上的学生的学号和姓名Q?br />    select SC.S#,Student.Sname from SC,Student where SC.S#=Student.S# and Score>80 and C#='003';
39、求选了评的学生h?br />    select count(*) from sc;
40、查询选修“叶^”老师所授课E的学生中，成W最高的学生姓名及其成W
    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^' and SC.score=(select max(score)from SC where C#=C.C# );
41、查询各个课E及相应的选修人数
    select count(*) from sc group by C#;
42、查询不同课E成l相同的学生的学受课E号、学生成l?br />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W最好的前两?br />    SELECT t1.S# as 学生ID,t1.C# as 评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E的学生选修人数Q超q?0人的评才统计）。要求输E号和选修人数Q查询结果按人数降序排列Q查询结果按人数降序排列Q若人数相同Q按评号升序排?br />    select C# as 评?count(*) as 人数
    from sc
    group by C#
    order by count(*) desc,c#
45、检索至选修两门评的学生学?br />    select S#
    from sc
    group by s#
    having count(*) > = 2
46、查询全部学生都选修的课E的评号和评?br />    select C#,Cname
    from Course
    where C# in (select c# from sc group by c#)
47、查询没学过“叶^”老师讲授的Q一门课E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^');
48、查询两门以上不及格评的同学的学号及其q_成W
    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?#8220;004”评分数于60Q按分数降序排列的同学学?br />    select S# from SC where C#='004'and score <60 order by score desc;
50、删?#8220;002”同学?#8220;001”评的成l?br />delete from Sc where S#='001'and C#='001';

 

本题用到下面三个关系表：

CARD     借书卡?span>   CNO 卡号QNAME 姓名QCLASS 班

BOOKS    图书?span>     BNO 书号QBNAME 书名,AUTHOR 作者，PRICE 单hQQUANTITY 库存册数

BORROW   借书记录?CNO 借书卡号QBNO 书号QRDATE q书日期

备注Q限定每人每U书只能借一本；库存册数随借书、还书而改变?/span>

要求实现如下15个处理：

 1Q?写出建立BORROW表的SQL语句Q要求定义主码完整性约束和引用完整性约束?/span>

 2Q?扑և借书过5本的读?输出借书卡号及所借图书册数?/span>

 3Q?查询借阅?水浒"一书的读者，输出姓名及班U?/span>

 4Q?查询q期未还图书Q输出借阅者（卡号Q、书号及q书日期?/span>

 5Q?查询书名包括"|络"关键词的图书Q输Z受书名、作者?/span>

 6Q?查询现有图书中h格最高的图书Q输Z名及作者?/span>

 7Q?查询当前借了"计算Ҏ"但没有?计算Ҏ习题?的读者，输出其借书卡号Qƈ按卡号降序排序输出?/span>

 8Q??C01"班同学所借图书的q期都g长一周?/span>

 9Q?从BOOKS表中删除当前无h借阅的图书记录?/span>

 10Q如果经常按书名查询图书信息Q请建立合适的索引?/span>

 11Q在BORROW表上建立一个触发器Q完成如下功能：如果读者借阅的书名是"数据库技术及应用"Q就该读者的借阅记录保存?/span>

BORROW_SAVE表中Q注ORROW_SAVE表结构同BORROW表）?/span>

 12Q徏立一个视图，昄"?1"班学生的借书信息Q只要求昄姓名和书名）?/span>

 13Q查询当前同时借有"计算Ҏ"?l合数学"两本书的读者，输出其借书卡号Qƈ按卡号升序排序输出?/span>

 14Q假定在建BOOKS表时没有定义ȝQ写ZؓBOOKS表追加定义主码的语句?/span>

 15Q对CARD表做如下修改Q?/span>

    a. NAME最大列宽增加到10个字W（假定原ؓ6个字W）?/span>

    b. 表增?列NAMEQ系名）Q可变长Q最?0个字W?/span>

 

 

1. 写出建立BORROW表的SQL语句Q要求定义主码完整性约束和引用完整性约?/span>

--实现代码Q?/span>

CREATE TABLE BORROW(

    CNO int FOREIGN KEY REFERENCES CARD(CNO),

    BNO int FOREIGN KEY REFERENCES BOOKS(BNO),

    RDATE datetime,

    PRIMARY KEY(CNO,BNO))

 

2. 扑և借书过5本的读?输出借书卡号及所借图书册?/span>

--实现代码Q?/span>

SELECT CNO,借图书册?COUNT(*)

FROM BORROW

GROUP BY CNO

HAVING COUNT(*)>5

 

3. 查询借阅?水浒"一书的读者，输出姓名及班U?/span>

--实现代码Q?/span>

SELECT * FROM CARD c

WHERE EXISTS(

    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q期未还图书Q输出借阅者（卡号Q、书号及q书日期

--实现代码Q?/span>

SELECT * FROM BORROW

WHERE RDATE<GETDATE()

 

5. 查询书名包括"|络"关键词的图书Q输Z受书名、作?/span>

--实现代码Q?/span>

SELECT BNO,BNAME,AUTHOR FROM BOOKS

WHERE BNAME LIKE N'%|络%'

 

6. 查询现有图书中h格最高的图书Q输Z名及作?/span>

--实现代码Q?/span>

SELECT BNO,BNAME,AUTHOR FROM BOOKS

WHERE PRICE=(

    SELECT MAX(PRICE) FROM BOOKS)

 

7. 查询当前借了"计算Ҏ"但没有?计算Ҏ习题?的读者，输出其借书卡号Qƈ按卡号降序排序输?/span>

--实现代码Q?/span>

SELECT a.CNO

FROM BORROW a,BOOKS b

WHERE a.BNO=b.BNO AND b.BNAME=N'计算Ҏ'

    AND NOT EXISTS(

        SELECT * FROM BORROW aa,BOOKS bb

        WHERE aa.BNO=bb.BNO

            AND bb.BNAME=N'计算Ҏ习题?

            AND aa.CNO=a.CNO)

ORDER BY a.CNO DESC

 

8. ?C01"班同学所借图书的q期都g长一?/span>

--实现代码Q?/span>

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h借阅的图书记?/span>

--实现代码Q?/span>

DELETE A FROM BOOKS a

WHERE NOT EXISTS(

    SELECT * FROM BORROW

    WHERE BNO=a.BNO)

 

10. 如果l常按书名查询图书信息，请徏立合适的索引

--实现代码Q?/span>

CREATE CLUSTERED INDEX IDX_BOOKS_BNAME ON BOOKS(BNAME)

 

11. 在BORROW表上建立一个触发器Q完成如下功能：如果读者借阅的书名是"数据库技术及应用"Q就该读者的借阅记录保存在BORROW_SAVE

表中Q注ORROW_SAVE表结构同BORROW表）

--实现代码Q?/span>

CREATE TRIGGER TR_SAVE ON BORROW

FOR INSERT,UPDATE

AS

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，昄"?1"班学生的借书信息Q只要求昄姓名和书名）

--实现代码Q?/span>

CREATE VIEW V_VIEW

AS

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'?1'

 

13. 查询当前同时借有"计算Ҏ"?l合数学"两本书的读者，输出其借书卡号Qƈ按卡号升序排序输?/span>

--实现代码Q?/span>

SELECT a.CNO

FROM BORROW a,BOOKS b

WHERE a.BNO=b.BNO

    AND b.BNAME IN(N'计算Ҏ',N'l合数学')

GROUP BY a.CNO

HAVING COUNT(*)=2

ORDER BY a.CNO DESC

 

14. 假定在徏BOOKS表时没有定义ȝQ写ZؓBOOKS表追加定义主码的语句

--实现代码Q?/span>

ALTER TABLE BOOKS ADD PRIMARY KEY(BNO)

 

15.1 NAME最大列宽增加到10个字W（假定原ؓ6个字W）

--实现代码Q?/span>

ALTER TABLE CARD ALTER COLUMN NAME varchar(10)

 

15.2 表增?列NAMEQ系名）Q可变长Q最?0个字W?/span>

--实现代码Q?/span>

ALTER TABLE CARD ADD pd varchar(20)

 

问题描述Q?/span>

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?/span>

C (C#,CN )        C#,CN       分别代表评~号、课E名U?/span>

SC ( S#,C#,G )    S#,C#,G     分别代表学号、所选修的课E编受学习成l?/span>

 

要求实现如下5个处理：

 1. 使用标准SQL嵌套语句查询选修评名称?#8217;E收基础’的学员学号和姓名

 2. 使用标准SQL嵌套语句查询选修评~号?#8217;C2’的学员姓名和所属单?/span>

 3. 使用标准SQL嵌套语句查询不选修评~号?#8217;C5’的学员姓名和所属单?/span>

 4. 使用标准SQL嵌套语句查询选修全部评的学员姓名和所属单?/span>

 5. 查询选修了课E的学员人数

 6. 查询选修评过5门的学员学号和所属单?/span>

 

1. 使用标准SQL嵌套语句查询选修评名称?#8217;E收基础’的学员学号和姓名

--实现代码Q?/span>

SELECT SN,SD FROM S

WHERE [S#] IN(

    SELECT [S#] FROM C,SC

    WHERE C.[C#]=SC.[C#]

        AND CN=N'E收基础')

 

 

2. 使用标准SQL嵌套语句查询选修评~号?#8217;C2’的学员姓名和所属单?/span>

--实现代码Q?/span>

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评~号?#8217;C5’的学员姓名和所属单?/span>

--实现代码Q?/span>

SELECT SN,SD FROM S

WHERE [S#] NOT IN(

    SELECT [S#] FROM SC

    WHERE [C#]='C5')

 

4. 使用标准SQL嵌套语句查询选修全部评的学员姓名和所属单?/span>

--实现代码Q?/span>

SELECT SN,SD FROM S

WHERE [S#] IN(

    SELECT [S#] FROM SC

        RIGHT JOIN C ON SC.[C#]=C.[C#]

    GROUP BY [S#]

    HAVING COUNT(*)=COUNT(DISTINCT [S#]))

 

5. 查询选修了课E的学员人数

--实现代码Q?/span>

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

 

6. 查询选修评过5门的学员学号和所属单?/span>

--实现代码Q?/span>

SELECT SN,SD FROM S

WHERE [S#] IN(

    SELECT [S#] FROM SC

    GROUP BY [S#]

    HAVING COUNT(DISTINCT [C#])>5)



]]>SQL的四U连?左外q接、右外连接、内q接、全q接http://www.aygfsteel.com/wshao/archive/2013/12/31/408280.html午后星期?/dc:creator>午后星期?/author>Tue, 31 Dec 2013 06:19:00 GMThttp://www.aygfsteel.com/wshao/archive/2013/12/31/408280.htmlhttp://www.aygfsteel.com/wshao/comments/408280.htmlhttp://www.aygfsteel.com/wshao/archive/2013/12/31/408280.html#Feedback0http://www.aygfsteel.com/wshao/comments/commentRss/408280.htmlhttp://www.aygfsteel.com/wshao/services/trackbacks/408280.html今天在看一个遗留系l的数据表的时候发现^时查扄视图是FULL OUT JOIN的，Dqx的数据记录要q行一些限制性处理，其实也可以设|视囑֐表ؓ叛_q接q在视图上设|各列的排序和筛选条件就可以辑ֈ效果?/p>

 

联接条g可在FROM或WHERE子句中指定，在FROM子句中指定联接条件。WHERE和HAVING子句也可以包含搜索条Ӟ以进一步筛选联接条件所选的行?nbsp;   
联接可分Z下几c：    


1、内联接Q典型的联接q算Q用像 =  ?<> 之类的比较运符Q。包括相{联接和自然联接?nbsp;    
内联接用比较运符Ҏ每个表共有的列的值匹配两个表中的行。例如，?students和courses表中学生标识L同的所有行?nbsp;  
    
2、外联接。外联接可以是左向外联接、右向外联接或完整外部联接?nbsp;    
?FROM子句中指定外联接Ӟ可以׃列几l关键字中的一l指定：     

1Q?span style="color: #000000">LEFT  JOIN或LEFT OUTER JOIN     
左向外联接的l果集包? LEFT OUTER子句中指定的左表的所有行Q而不仅仅是联接列所匚w的行。如果左表的某行在右表中没有匚w行，则在相关联的l果集行中右表的所有选择列表列均为空倹{?      

2Q?span style="color: #000000">RIGHT  JOIN ?RIGHT  OUTER  JOIN     
叛_外联接是左向外联接的反向联接。将q回双的所有行。如果右表的某行在左表中没有匚w行，则将为左表返回空倹{?nbsp;      
3Q?span style="color: #000000">FULL  JOIN ?FULL OUTER JOIN
完整外部联接q回左表和右表中的所有行。当某行在另一个表中没有匹配行Ӟ则另一个表的选择列表列包含空倹{如果表之间有匹配行Q则整个l果集行包含的数据倹{?nbsp;  
    
3、交叉联?  
交叉联接q回左表中的所有行Q左表中的每一行与双中的所有行l合。交叉联接也UCW卡积?nbsp;   

FROM 子句中的表或视图可通过内联接或完整外部联接按Q意顺序指定；但是Q用左或叛_外联接指定表或视图时Q表或视囄序很重要。有关用左或右向外联接排列表的更多信息Q请参见使用外联接?nbsp;    
    
例子Q?  

-------------------------------------------------
  a?    id   name     b?    id   job   parent_id   
              1   ?                   1     23     1   
              2   李四                 2     34     2   
              3   王武                 3     34     4       
  a.id同parent_id   存在关系   

--------------------------------------------------    
 1Q?内连?  
  select   a.*,b.*   from   a   inner   join   b     on   a.id=b.parent_id       
  l果?    
  1   ?                   1     23     1   
  2   李四                  2     34     2   
    
  2Q左q接   
  select   a.*,b.*   from   a   left   join   b     on   a.id=b.parent_id       
  l果?    
  1   ?                   1     23     1   
  2   李四                  2     34     2   
  3   王武                  null   

 

 3Q?nbsp;双?  
  select   a.*,b.*   from   a   right   join   b     on   a.id=b.parent_id       
  l果?    
  1   ?                   1     23     1   
  2   李四                  2     34     2   
  null                       3     34     4   
    
 4Q?nbsp;完全q接   
  select   a.*,b.*   from   a   full   join   b     on   a.id=b.parent_id   

  l果?    
  1   ?                  1     23     1   
  2   李四                 2     34     2   
  null               　　  3     34     4   
  3   王武                 null



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