数据库实验2

1.建学生表语句

CREATE TABLE  `student` (
Sno INT NOT NULL ,
Sname VARCHAR( 20 ) NOT NULL ,
Ssex VARCHAR( 3 ) ,
Sage INT( 2 ) NOT NULL ,
Sdept VARCHAR( 20 ) ,
Sclass VARCHAR( 30 ) ,
Intime DATE ,
PRIMARY KEY ( Sno )
) ENGINE = INNODB DEFAULT CHARSET = utf8

   有约束条件的创建表的语句

ALTER TABLE  `student` 
ADD CONSTRAINT Sex_rule CHECK (Ssex IN ('男','女')),
ADD CONSTRAINT Age_rule CHECK (Sage BETWEEN 15 AND 30),
ADD CONSTRAINT Enter_University_date_rule CHECK (Intime BETWEEN 1923 -4 -30 AND 2015 -11 -05);

CREATE TABLE  `student` (
Sno INT NOT NULL ,
Sname VARCHAR( 20 ) NOT NULL ,
Ssex VARCHAR( 3 ) constraint Sex_rule check(Ssex IN('男','女')),
Sage INT( 2 ) constraint Age_rule check(Sage BETWEEN 15 AND 30) ,
Sdept VARCHAR( 20 ) ,
Sclass VARCHAR( 30 ) ,
Intime DATE constraint Enter_University_date_rule check(Intime BETWEEN 1923-4-30 AND 2015-11-05),
PRIMARY KEY ( Sno )
) ENGINE = INNODB DEFAULT CHARSET = utf8;

1.1数据插入语句

INSERT INTO  `data`.`student` (
`Sno` ,`Sname` ,`Ssex` ,`Sage` ,`Sdept` ,`Sclass` ,`Intime`)
VALUES (

'20009001', '葛文卿', '女', '22', '国际贸易', '国贸2班', '2000-8-29'

), (

'20014019', '郑秀丽', '女', '21', '会计学', '会计1班', '2001-9-2'

), (

'20023001', '刘成凯', '男', '18', '计算机', '软件2班', '2002-8-27'

), (

'20026002', '李涛', '女', '19', '电子学', '电子1班', '2002-8-27'

), (

'20023002', '沈香娜', '女', '18', '计算机', '软件2班', '2002-8-27'

), (

'20026003', '李涛', '男', '19', '计算机', '软件1班', '2002-8-27'

), (

'20023003', '肖一竹', '女', '19', '计算机', '软件2班', '2002-8-27'

);

2. 课程表建立

CREATE TABLE  `course` (
Cno VARCHAR( 10 ) NOT NULL ,
Cname VARCHAR( 20 ) NOT NULL ,
Cpno VARCHAR( 10 ) ,
Ccredit FLOAT( 1 ) NOT NULL ,
PRIMARY KEY ( Cno )
) ENGINE = INNODB DEFAULT CHARSET = utf8

2.1 添加数据

INSERT INTO `data`.`course` (`Cno`, `Cname`, `Cpno`, `Ccredit`) VALUES 
('C801', '高等数学', NULL, '4'), 
('C802', 'C++语言', 'C807', '3'), 
('C803', '数据结构', 'C802', '4'), 
('C804', '数据库原理', 'C803', '4'),
('C805', '操作系统', 'C807', '4'), 
('C806', '编译原理', 'C803', '4'),
('C807', '离散数学', NULL, '4');

3. 创建成绩表

CREATE TABLE  `grade` (
Sno INT NOT NULL ,
Cno VARCHAR( 10 ) ,
Ggrade INT( 3 ) DEFAULT  '0',
Ccredit FLOAT( 1 ) NOT NULL ,
PRIMARY KEY ( Sno, Cno )
) ENGINE = INNODB DEFAULT CHARSET = utf8

 3.1 插入数据

INSERT INTO  `data`.`grade` (
`Sno` ,
`Cno` ,
`Ggrade` ,
`Ccredit`
)
VALUES (
'20023001',  'C801',  '98',  '4'
), (
'20023002',  'C804',  '70',  '4'
), (
'20026001',  'C801',  '85',  '4'
), (
'20023001',  'C802',  '99',  '3'
), (
'20026002',  'C803',  '82',  '4'
);

4.授课表

CREATE TABLE  `teach` (
Tname VARCHAR( 10 ) NOT NULL ,
Cno VARCHAR( 10 ) ,
Ttime INT( 3 ) DEFAULT  '0',
Tclass VARCHAR( 20 ) ,
PRIMARY KEY ( Cno, Tclass )
) ENGINE = INNODB DEFAULT CHARSET = utf8

4.1数据插入

INSERT INTO  `data`.`teach` (
`Tname` ,`Cno` ,`Ttime` ,`Tclass`)
VALUES (
'苏亚步',  'C801',  '72',  '软件1班'
), (
'苏亚步',  'C801',  '72',  '软件2班'
), (
'王文山',  'C802',  '64',  '软件2班'
), (
'张珊',  'C803',  '72',  '软件2班'
), (
'王文山',  'C804',  '64',  '软件2班'
);

 

1.  select * from `student` where Ssex = '女' and Sclass = '软件2班';

2.  select * from `student` where Intime < '2002-01-01';

3.  select * from `student` where Sage<19 OR Ssex = '女';

4.  select `Cname` from  `course` where Cpno IS NULL;

5.  select `Sno`,`Sname`,`Sdept` from `student` where Sdept not in ('电子学','会计学');

6.  select MAX(Ggrade) from `grade` where Cno = 'C801';

7.  select COUNT(*) '男生总人数', AVG(Sage) '男生平均年龄'from `student` where Ssex = '男' ;
    select COUNT(*)  '女生总人数', AVG(Sage)'女生平均年龄' from `student` where Ssex = '女' ;
    select Ssex , COUNT(Sno) As Number , AVG(Sage) As AvogofAge from student group by Ssex;

列出选修了一门以上课程的学生学号，及其选修门数   
8.  select Sno,COUNT(*)'课程数' from grade GROUP BY Cno HAVING COUNT(*)>1; 

9.  select `Sno`,`Sname` from `student` where `Sclass` IN (select `Sclass` from `student` where `Sname` = '沈香娜');//嵌套查询
   select `Sno`,`Sname` from `student` where Sname<>'沈香娜' AND `Sclass` IN (select `Sclass` from `student` where `Sname` = '沈香娜')

统计每一年龄段选修课程的学生人数
10  SELECT  Sage, COUNT(DISTINCT student.Sno) '人数' FROM student, grade WHERE student.Sno = grade.Sno GROUP BY Sage;

难题：

1.在基本表“成绩表”中检索平均成绩最高的学生学号；
 select Sno ,AVG(Ggrade) from `grade` group by Sno having AVG(Ggrade)>=ALL(select AVG(Ggrade) from `grade` group by Sno );

2.SELECT Sage, COUNT( Sno ) AS  '人数' FROM student GROUP BY Sage HAVING COUNT( * ) >2 order by Sage ASC,Sno DESC;

3. 列出选修了全部课程的学生学号和姓名；
   select Sname ,Sno
   from student
   where NOT EXISTS(SELECT * FROM course where not exists(
   select * from grade where grade.Sno = student.Sno and grade.Cno = course.Cno
));

4. 查询这样的学生，该生至少选修了学生20026001所选修的全部课程。
SELECT DISTINCT Sno
FROM grade gradeX
WHERE NOT 
EXISTS (

SELECT * 
FROM grade gradeY
WHERE gradeY.Sno =  '20026001'
AND NOT 
EXISTS (

 SELECT * 
 FROM grade gradeZ
 WHERE gradeZ.Sno = gradeX.Sno
 AND gradeZ.Cno = gradeY.Cno
 )
)