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  • 数据库表的查询操作实践演练(实验三),数据库演练

    继前两次的实验,本次实验以熟练掌握利用select语句进行各种查询操作:单表查询、多表连接及查询、嵌套查询、集合查询等,巩固数据库查询操作。
    下面就跟着小编一起练习吧!
    在实验一创建并插入数据的表(Student, Course,SC,Teacher,TC)的基础上,完成以下操作。
    (1)将教师‘罗莉'的名字改为‘罗莉莉'。
    复制代码 代码如下:update Teacher set tname='罗莉莉' where tname='罗莉'
    (2)将两个同学(数据自己临时设置,用后即删除)的两门课程的成绩以运行sql程序文件的形式插入score表中。该题用以验证、理解和掌握关系模型的完整性规则;
     插入:
    复制代码 代码如下:insert into Score(sno,cno,grade) values ('04261006','C003','64')
    insert into Score(sno,cno,grade) values('04261007','C004','79')
    查询:
    复制代码 代码如下:select sno 学号,cno 课程号,grade 分数from Score where sno=04261006 or sno=04261007;
    删除:
    复制代码 代码如下:delete from Score where sno=04261006 or sno=04261007;
    (3)求每门课的平均成绩,并把结果存入average表(自行设计并创建);
    复制代码 代码如下:CREATE TABLE average
    (
    cno CHAR(8),
    avscore numeric(5,2),
    constraint a1 primary key (cno),
    constraint a2 foreign key (cno) references Course(cno),
    )
    insert into average(cno,avscore)
    select distinct cno ,avg(grade) from Score group by cno
    (4)将学生“马丽”的年龄改为24;
    复制代码 代码如下:Update Student set 2014-year(Sbirth) 年龄 where Sname=' 马丽' 
    (5)将所有学生的szipcode属性列值填补上;
    复制代码 代码如下:update Student set szipcode='221000'
    (6)将average表中的所有课程的平均成绩置零;
    复制代码 代码如下: update average set avscore='0'
    (7)删除average表中的课程号为‘C007'的平均成绩记录;
    复制代码 代码如下:delete from average where cno='C007'
    (8)删除所有average表中平均成绩记录;
    复制代码 代码如下:delete from average;
    (9)建立一个临时学生信息表(tstudent),删除该表中的学号含‘101'的所有学生记录。
    复制代码 代码如下:create  table  tstudent   ( Sno  char(8)  primary  key,     Sname  varchar(8)  unique );  
    Delete  from  tstudent  where  Sno  like '001011%';
    (10)查询全体学生的学号与姓名;
    复制代码 代码如下:select sno 学号,sname 姓名from Student
    (11)查询全体学生的学号、姓名、所属系;
    复制代码 代码如下:select sno 学号,sname 姓名,sdept 系from Student
    (12)查询全体学生的详细记录;
    复制代码 代码如下:select * from Student
    (13)查询全体学生的姓名及其年龄;
    复制代码 代码如下:select sname 姓名,2014-year(sbirth) 年龄from Student
    (14)查询全体学生的姓名、出生年份;
    复制代码 代码如下:select sname 姓名,year(sbirth) 出生年份from Student
    (15)查询所有修过课的学生的学号;
    复制代码 代码如下:select distinct sno from Score
    select distinct student.sno from Student,Score where Student.sno=Score.sno and Score.grade>0 ;
    (16)查询“计算机系”班全体学生名单;
    复制代码 代码如下:select sno,sname from Student where sdept='计算机系'
    (17)查询查询所有年龄在23岁以下的学生姓名及其年龄;
    复制代码 代码如下:select sname 姓名,2014-year(sbirth) 年龄from Student where 2014-year(sbirth)<23;
    (18)查询考试成绩有不及格的学生的学号;
    复制代码 代码如下:select distinct sno from Score where grade<60;
    (19)查询年龄在20至22岁之间的学生姓名、系和年龄;
    复制代码 代码如下:select sname 姓名,sdept 系,2014-year(sbirth) 年龄from student where 2014-year(sbirth) between 20 and 22;
    (20)查询年龄不在20至22岁之间的学生姓名、系和年龄;
     复制代码 代码如下:select sname 姓名,sdept 系,2014-year(sbirth) 年龄from student where 2014-year(sbirth) not between 20 and 22;
    (21)查询“计算机系”和“电商系”的学生的姓名;
    复制代码 代码如下:select sname from Student where sdept='计算机系' or sclass='电商系'
    (22)查询既不是“计11”也不是“计61”班的学生的姓名和班级信息;
    复制代码 代码如下:select sname,sclass from Student where sclass not in('计','计');
    (23)查询学号为“04262002”的学生的详细情况;
    [code]select student.sno,sname,ssex,2014-year(sbirth),sclass,grade from Student,Score where Student.sno=Score.sno and Student.sno='04262002';
    (24)查询学号以“04262”打头的学生信息;
    复制代码 代码如下:select * from Student where sno like '04262%'
    (25)查询所有姓“张”学生的学号、姓名、性别、年龄;
    复制代码 代码如下:select sno 学号,sname 姓名,ssex 性别,2011-year(sbirth) 年龄from Student where sname like'王%'
    (26)查询名字中第二个字有“海”字的学生的学号、姓名、性别、年龄;
    复制代码 代码如下: select sno 学号,sname 姓名,ssex 性别,2011-year(sbirth) 年龄from Student where sname like '_田%'
    (27)查询所有不姓“刘”学生的姓名;
    复制代码 代码如下:select sname 姓名from Student where sname not like '刘%'
    (28)查询课程号以“C”开头的最后两个字母为“05”的课程号和课程名;
    复制代码 代码如下:select cno,cname from Course where cno like 'C%05'
    (29)某些学生选修某门课程后没有参加考试,所以有选修课记录,但没有考试成绩,试查找缺少考试成绩的学生和相应的课程号;
    复制代码 代码如下:select Student.sno,sname,cno from Student,Score where Student.sno=Score.sno and grade is NULL;
    (30)查找全部有成绩记录的学生学号、课程号;
    复制代码 代码如下:select sno, cno from Score where grade is not NULL;
    (31)查找“计算机系”年龄在22岁以下的学生学号、姓名;
    复制代码 代码如下:select sno ,sname from Student where sdept='计算机系' and 2014-year(sbirth)<22
    (32)查找选修了“C001”号课程的学生学号及其成绩,查询结果按分数降序排序;
    复制代码 代码如下:select student.sno,grade from student,Score where Student.sno=Score.sno and cno='C001' order by grade desc;
    (33)查询全体学生情况,查询结果按所在系升序排列,对同一系中的学生按年龄降序排列;
    复制代码 代码如下:select * from student order by sdept asc,2014-year(sbirth) desc;
    (34)查询学生总人数;
    复制代码 代码如下:select count(*) 人数from Student;
    (35)查询选修了课程的学生人数;
    复制代码 代码如下:select count(distinct sno)人数from Score;
    (36)在所有课程中查询最高分的学生学号和成绩;
    复制代码 代码如下:select sno,grade from Score where grade =(select max(grade)from Score )

    复制代码 代码如下:select distinct a.* from Score a where a.sno IN (select top 1 Score.sno from Score where Score.cno = a.cno order by grade desc)
    (37)查询学习“C001”课程的学生最高分数;
     复制代码 代码如下:select max(grade)最高分数from Score where cno='C001'
    (38)计算各个课程号与相应的选课人数;
    复制代码 代码如下:select count(sno) 选课人数from Score group by cno;
    (39)查询“计算机系”选修了两门课程以上的学生学号、姓名;
    复制代码 代码如下:select Student.sno,sname from Student where Student.sno in
    (select Student.sno from Student,Score where 
    sdept='计算机系'and Student.sno=Score.sno group by Student.sno having count(cno)>=2);
    (40)自然连接student和score表;
    复制代码 代码如下:select student.*,Score.grade from student ,Score where student.sno=Score.sno;
    (41)使用自身连接查询每一门课程的间接先行课(即先行课的先行课)
    复制代码 代码如下: select a.cno,b.cpno from Course a,Course b where a.cpno=b.cno;
    (42)使用复合条件连接查询选修“c001”号课程且成绩在90分以上的所有同学;
    复制代码 代码如下: select sname,grade from student,Score where Student.sno=Score.sno and cno='C001' and grade>=90;
    (43)使用复合条件连接查询每个学生选修的课程名及其成绩;
     复制代码 代码如下: select Student.sno,sname,cname,grade from Course,Score,Student where Course.cno=Score.cno and student.sno=Score.sno;
    (44)查询选修了全部课程的学生;
    复制代码 代码如下:select Sname from Student where not exists (select *  from Course where not exists(select *  from Score where Sno=Student.Sno and Cno=Course.Cno)) 
    (45)查询所有选修了C001号课程的学生学号、姓名;
    复制代码 代码如下:select student.sno,sname from student,Score where student.sno=Score.sno and cno='C001';
    (46)查询选修了课程C001或C007的学生学号、姓名;
    [code]select student.sno,sname,cno from student,Score where student.sno=Score.sno and cno in ('C001','C007');[/code]
    (47)查询“计算机系”的学生及年龄不大于23岁的学生;
    复制代码 代码如下:select sno ,sname,2014-year(sbirth) age ,sclass from student where sdept='计算机系' or 2014-year(sbirth)<=23;
    (48)查询既选修了课程C001又选修了课程C007的所有学生学号、姓名;
    复制代码 代码如下:select student.sno,sname from student,Score where student.sno=Score.sno and cno='C001' and student.sno in (select student.sno from student,Score where student.sno=Score.sno and cno='C007')
    (49)查询选修了课程名为“数据库原理”的学生的学号、姓名、性别、年龄;
    复制代码 代码如下:select student.sno ,sname,ssex,cname,2011-year(sbirth) age from student,Score,Course where student.sno=Score.sno and Score.cno=Course.cno and cname='数据库原理';
    (50)查询其他班中比“计算机系”所有学生年龄都小的学生名单;
    复制代码 代码如下:select sno,sname ,2014-year(sbirth) age from student where 2014-year(sbirth)<(select min(2014-year(sbirth)) from student where sclass='计61')and sclass !='计61';
    (51)查询与“夏天”在同一个系学习的学生学号、姓名、性别、年龄;
    复制代码 代码如下:select sno,sname,ssex,2014-year(sbirth) age from student where sdept=(select sdept from student where sname='夏天') and sname!='夏天'
    (52)建立“计算机系”学生的视图1;
    复制代码 代码如下:create view view_student
    as select sno,sname,ssex,sbirth,sclass from student where sclass='13z网络'
    (53)建立“计算机系”学生的视图2,并要求进行修改与插入时,仍须保证该视图只有“计算机系”班学生;
    复制代码 代码如下:create view view_student2
    as select sno,sname,ssex,sbirth,sclass from student where sclass='13z网络' with check option;
    (54)建立“计算机系”选修了“C001”课程的学生的视图,定义视图名为“v_cs_C001_student1”;
    复制代码 代码如下:create view v_cs_C001_student1
    as select student.sno,sname,ssex,sbirth,sclass from Student ,Score where 
    student.sno=Score.sno and sclass='13z网络' and cno='C001';
    (55)建立“计算机系”班选修了“C001”课程且成绩在90分以上的学生的视图,定义视图名为“cs_c001_student2”;
    复制代码 代码如下:create view cs_c001_student2
    as 
    select student.sno,sname ,ssex,sbirth,sclass,cno from student,Score where 
    student.sno=Score.sno and cno='C001' and sclass='13z网络'and student.sno in (select student.sno from student,Score where student.sno=Score.sno and grade>90)
    (56)定义一个反映学生年龄的视图,定义视图名为“v_birth_student”;
    复制代码 代码如下:create view v_birth_student
    as
    select sno,sname,2014-year(sbirth) age from student
    (57)将学生表中所有女生记录定义为一个视图,视图名为“v_female_student”;
    复制代码 代码如下:create view v_female_student 
    as 
    select * from student where ssex='女';
    (58)将学生的学号及其平均成绩定义为一个视图,视图名为“v_average_student”;
    复制代码 代码如下:create view v_average_student
    as
    select sno,avg(grade) avscore from Score group by sno;
    (59)在“计算机系”学生视图中找出年龄小于22岁的学生;
    复制代码 代码如下:select * from view_student where 2014-year(sbirth)<=22;
    (60)利用视图查询“计算机系”选修了“C001”课程的学生;
    复制代码 代码如下:select * from v_cs_C001_student1;
    (61)通过(52)中的“计算机系”视图修改某个学生的名字;
    复制代码 代码如下:update view_student set sname='王某某'where sno=04261001;
    (62)通过(53)中的“计算机系”视图,插入一个新学生记录。
    复制代码 代码如下:insert into view_student2(sno,sname,ssex,sbirth,sclass) values ('04262004','张某某','男','1987/11/09','计');
    (63)通过(53)中的“计算机系”视图,删除一个学生记录。
    复制代码 代码如下:delete from view_student2 where sno='04262004'and sname='张某某';

    实验课结束了,相信通过本节课的实践操作,小伙伴们都对数据库表的操作有了更进一步的了解。
    以上就是查询数据库表的基本操作,几乎涵盖了各种查询操作所遇到的情况,值得大家亲自操作一下,相信对大家的学习有所帮助。

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  • 原文地址:https://www.cnblogs.com/peizhe123/p/4943621.html
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