MySQL综合应用练习(直接拷贝到自己空间)

Posted 2022-10-12 小猿网

mysql综合应用练习_直接拷贝到自己空间

• • • 资源说明
    • 资源分享（拷贝）
    • 1、表结构（截图）
    • 2、表数据
    • 3、问题&实现SQL
    • 4、插曲（难点:主键&外键）
    • • 1、创建&删除数据库
      • 2、创建&删除数据表
      • 3、主键&外键

资源说明

由于之前做的时候是已笔记的形式做的，所以我就直接把SQL练习文件导出来分享给大家，如果是自己需要从零开始建表插入数据的话建议看一下框起来的命令说明，照葫芦画瓢仿一下，因为对于很多人来说主键和外键是一个难点。如果主键和外键在该笔记中实在看不懂可以百度一下或者其他地方找点资料看看学习一下。

资源分享（拷贝）

由于该笔记可以分享所以，所以直接拷贝考自己空间即可，连接如下：
MySQL综合应用练习：https://flowus.cn/value/share/b42c85cb-b3e0-4f15-98c8-fb10cf290f99

1、表结构（截图）

1、student(学生表)

2、teacher(教师表)

3、course(课程表)

4、score(成绩表)

2、表数据

1、student

2、teacher

3、course

4、score

3、问题&实现SQL

--第一题 查询Student表中的所有记录的Sname、Ssex和Class列。
select Sname,Ssex,Class from student

--第二题 查询教师所有的单位即不重复的Depart列。
select distinct Depart from Teacher

--第三题 查询Student表的所有记录。
select * from student

--第四题 查询Score表中成绩在60到80之间的所有记录。
select * from Score where Degree between 60 and 80

--第五题 查询Score表中成绩为85，86或88的记录。
select * from Score where Degree in ('85','86','88')

--第六题 查询Student表中“95031”班或性别为“女”的同学记录。
select * from student where Class='95031' or Ssex='女'

--第七题 以Class降序查询Student表的所有记录。
select * from student order by Class desc

--第八题 以Cno升序、Degree降序查询Score表的所有记录。
select * from Score order by Cno asc,Degree desc

--第九题 查询“95031”班的学生人数。
select count(*) from student where Class='95031' --*可以换成主键值

--第十题 查询Score表中的最高分的学生学号和课程号。（子查询或者排序）
select SNO,CNO from Score where Degree=(select MAX(Degree) from Score)

--第十一题 查询每门课的平均成绩。
select Cno,AVG(Degree) as 平均分 from Score group by Cno

select Cname from Course where Cno in (select Cno a from Score group by Cno) 
union
select Cno,AVG(Degree) from Score group by Cno

--第十二题 查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
select AVG(Degree ) from Score where Cno like '3%' group by Cno having COUNT(Cno)>4

--第十三题 查询分数大于70，小于90的Sno列。
select sno from Score where Degree between 70 and 90

--第十四题 查询所有学生的Sname、Cno和Degree列。
select Sname,Cno,Degree from student join Score on student.Sno=Score.Sno

--第十五题 查询所有学生的Sno、Cname和Degree列。
select Sno,Cname,degree from Score join Course on Course.Cno=Score.Cno

--第十六题 查询所有学生的Sname、Cname和Degree列。
select student.Sname,Cname,degree from student join Score on student.Sno=Score.Sno join Course on Course.Cno=Score.Cno

--第十七题 查询“95033”班学生的平均分。
select AVG(Degree) from Score where Sno in (select Sno from student where Class='95033')

select AVG(Degree) from Score,student where student.Sno=Score.Sno and Class='95033'

--第十八题 假设使用如下命令建立了一个grade表：
create table grade(low int,upp int,rank char(1))
insert into grade values(90,100,'A')
insert into grade values(80,89,'B')
insert into grade values(70,79,'C')
insert into grade values(60,69,'D')
insert into grade values(0,59,'E')
--现查询所有同学的Sno、Cno和rank列。

select Sno,Cno,Degree,[RANK] from grade join Score on Score.Degree between low and upp

select Sno,Cno,Degree,[RANK] from Score,grade where Degree between low and upp


--第十九题 查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
select * from student,Score where Score.Cno='3-105' and student.Sno=Score.Sno and Score.Degree>(select Degree from Score where Cno='3-105' and Sno='109')

--第二十题 查询score中选学多门课程的同学中分数为非最高分成绩的记录。
select * from Score a where Degree <(select MAX(degree) from Score b where a.Cno=b.Cno) and Sno in(select Sno from Score group by Sno having count(*)>1)

--第二十一题 查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
select * from student,Score where student.Sno=Score.Sno and Score.Degree>(select Degree from Score where Cno='3-105' and Sno='109')

--第二十二题 查询和学号为107的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
select Sno,Sname,Sbirthday from student where year(student.Sbirthday)=(select year(Sbirthday) from student where Sno='107')

--第二十三题 查询“张旭“教师任课的学生成绩。
--select Degree from Score,Teacher,Course where Teacher.Tname='张旭' and Teacher.Tno=Course.Tno and Course.Cno=Score.Cno

select Sno,Cno,Degree from Score where Cno in (select Cno from Course where Tno in (select Tno from Teacher where Tname='张旭'))

--第二十四题 查询选修某课程的同学人数多于5人的教师姓名。
select Tname from Teacher where Tno in (select Tno from Course where Cno in (select Cno from Score group by Cno having COUNT(*)>5) )

--第二十五题 查询95033班和95031班全体学生的记录。
select * from student where Class='95033' or Class='95031'

--第二十六题 查询存在有85分以上成绩的课程Cno.
select distinct cno from Score where Degree>85

--第二十七题 查询出“计算机系“教师所教课程的成绩表。
select sno,Cno ,Degree from Score where Cno in (select Cno from Course where Tno in (select tno from Teacher where Depart='计算机系'))

--第二十八题 查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。使用相关子查询
select Tname,Prof from Teacher a where Prof not in(select Prof from Teacher b where a.Depart!=b.Depart)

--第二十九题 查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”课程的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
select Cno,Sno,Degree from Score a where (select Degree from Score b where Cno='3-105' and b.Sno=a.Sno)>=(select Degree from Score c where Cno='3-245' and c.Sno=a.Sno) order by Degree desc

select * from Score where Cno='3-105' and Degree >any(select Degree from Score where Cno='3-245')

--第三十题 查询选修编号为“3-105”课程且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
select Cno,Sno,Degree from Score a where (select Degree from Score b where Cno='3-105' and b.Sno=a.Sno)>(select Degree from Score c where Cno='3-245' and c.Sno=a.Sno)

--第三十一题 查询所有教师和同学的name、sex和birthday.
select distinct Sname as name,Ssex as sex,Sbirthday as birthday from student
union
select distinct Tname as name,Tsex as sex,Tbirthady as birthday from Teacher

--第三十二题 查询所有“女”教师和“女”同学的name、sex和birthday.
select distinct Sname as name,Ssex as sex,Sbirthday as birthday from student where Ssex='女'
union
select distinct Tname as name,Tsex as sex,Tbirthady as birthday from Teacher where Tsex='女'

--第三十三题 查询成绩比该课程平均成绩低的同学的成绩表。
select Sno,Cno,Degree from Score a where a.Degree<(select AVG(Degree) from Score b where a.Cno=b.Cno)

--第三十四题 查询所有任课教师的Tname和Depart.
select Tname,Depart from Teacher where Tname in (select distinct Tname from Teacher,Course,Score where Teacher.Tno=Course.Tno and Course.Cno=Score.Cno)

select Tname,Depart from Teacher where tno in (select tno from course where Cno in (select distinct Cno from Score))

--第三十五题 查询所有未讲课的教师的Tname和Depart. 
select Tname,Depart from Teacher where Tname not in (select distinct Tname from Teacher,Course,Score where Teacher.Tno=Course.Tno and Course.Cno=Score.Cno)
--第三十六题 查询至少有2名男生的班号。
select Class FROM student where Ssex='男' group by Class having COUNT(*)>1

--第三十七题 查询Student表中不姓“王”的同学记录。
select * from student where Sname not like ('王%')

--第三十八题 查询Student表中每个学生的姓名和年龄。
select Sname,YEAR(GETDATE())-year(Sbirthday) from student

--第三十九题 查询Student表中最大和最小的Sbirthday日期值。
select MAX(Sbirthday) as 最大,MIN(Sbirthday) as 最小 from student

--第四十题 以班号和年龄从大到小的顺序查询Student表中的全部记录。
select * from student order by Class desc,Sbirthday asc

--第四十一题 查询“男”教师及其所上的课程。
select Tname,Cname from Teacher,Course where Tsex='男' and Teacher.Tno=Course.Tno

--第四十二题 查询最高分同学的Sno、Cno和Degree列。
select Sno,Cno,Degree from Score where degree=(select MAX(Degree)from Score)

select top 1* from Score order by Degree desc

--第四十三题 查询和“李军”同性别的所有同学的Sname.
select Sname from student where Ssex=(select Ssex from student where Sname='李军') and Sname not in ('李军')

--第四十四题 查询和“李军”同性别并同班的同学Sname.
select Sname from student where Ssex=(select Ssex from student where Sname='李军') and Sname not in ('李军') and Class=(select Class from student where Sname='李军')

--第四十五题 查询所有选修“计算机导论”课程的“男”同学的成绩表。
select Sno,Degree from Score where Sno in (select Sno from student where Ssex='男') and Cno in (select Cno from Course where Cname='计算机导论')

4、插曲（难点:主键&外键）

1、创建&删除数据库

CREATE DATABASE IF NOT EXISTS RUNOOB DEFAULT CHARSET utf8 COLLATE utf8_general_ci;
#创建数据库
CREATE DATABASE AA;
#创建数据库
drop database AA;
#删除数据库

2、创建&删除数据表

CREATE TABLE IF NOT EXISTS `student` (
  `Sno` VARCHAR(20)	CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '学号',
  `Sname` VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '学生姓名',
  `Ssex` VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '学生性别',
  `Sbirthday` datetime DEFAULT NULL COMMENT '学生出生年月',
  `Class` VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '学生所在班级',
  PRIMARY KEY (`Sno`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='学生表';
#创建student数据表(学生表)

DROP TABLE table_name;
#数据数据表

3、主键&外键

CREATE TABLE `teacher` (
  `Tno` VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '教工编号(主码)',
  `Tname` VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '教工姓名',
  `Tsex` VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '教工性别',
  `Tbirthday` datetime DEFAULT NULL COMMENT '教工生日',
  `Prof` VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '教工职称',
  `Depart` VARCHAR(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '教工所在专业'
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='教师表';
#创建相应的表

ALTER TABLE `teacher` DROP PRIMARY KEY,ADD PRIMARY KEY(`Tno`);
#删除相应的主键并添加主键
ALTER TABLE `teacher` ADD PRIMARY KEY(`Tno`);
#添加主键
alter table 表名 drop primary key
#删除主键

CREATE TABLE `course` (
  `Cno` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '课程号(主键)',
  `Cname` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '课程名称',
  `Tno` varchar(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '教工号(外码)',
  PRIMARY KEY (`Cno`),
  CONSTRAINT `course_tno` FOREIGN KEY (`Tno`) REFERENCES `teacher` (`Tno`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='课程表';
/*创建表、添加外键*/

alter table score add constraint fk_sno foreign key(Sno) references student(Sno);
#在score(从表)中设置Sno为外键，与表student(主表 一定是主键)的 主键 Sno进行关联
alter table score add constraint fk_cno foreign key(Cno) references course(Cno);
#在score(从表)中设置Cno为外键，与表course(主表 一定是主键)的 主键 Sno进行关联
ALTER TABLE score DROP FOREIGN KEY fk_cno;
#删除score中名为fk_cno的外键