【Python全栈100天学习笔记】Day37MySQL详解（sql语句基本操作含索引、视图、存储过程）

-- 如果存在名为school的数据库就删除它
drop database if exists school;

-- 创建名为school的数据库并设置默认的字符集和排序方式
create database school default charset utf8;

-- 切换到school数据库上下文环境
use school;

-- 创建学院表
create table tb_college
(
collid 		int auto_increment comment '编号',
collname 	varchar(50) not null comment '名称',
collintro 	varchar(500) default '' comment '介绍',
primary key (collid)
);

-- 创建学生表
create table tb_student
(
stuid 		int not null comment '学号',
stuname 	varchar(20) not null comment '姓名',
stusex 		boolean default 1 comment '性别',
stubirth 	date not null comment '出生日期',
stuaddr 	varchar(255) default '' comment '籍贯',
collid 		int not null comment '所属学院',
primary key (stuid),
foreign key (collid) references tb_college (collid)
);

-- 创建教师表
create table tb_teacher
(
teaid 		int not null comment '工号',
teaname 	varchar(20) not null comment '姓名',
teatitle 	varchar(10) default '助教' comment '职称',
collid 		int not null comment '所属学院',
primary key (teaid),
foreign key (collid) references tb_college (collid)
);

-- 创建课程表
create table tb_course
(
couid 		int not null comment '编号',
couname 	varchar(50) not null comment '名称',
coucredit 	int not null comment '学分',
teaid 		int not null comment '授课老师',
primary key (couid),
foreign key (teaid) references tb_teacher (teaid)
);

-- 创建选课记录表
create table tb_record
(
recid 		int auto_increment comment '选课记录编号',
sid 		int not null comment '选课学生',
cid 		int not null comment '所选课程',
seldate 	datetime default now() comment '选课时间日期',
score 		decimal(4,1) comment '考试成绩',
primary key (recid),
foreign key (sid) references tb_student (stuid),
foreign key (cid) references tb_course (couid),
unique (sid, cid)
);

show character set;

+----------+---------------------------------+---------------------+--------+
| Charset  | Description                     | Default collation   | Maxlen |
+----------+---------------------------------+---------------------+--------+
| big5     | Big5 Traditional Chinese        | big5_chinese_ci     |      2 |
| dec8     | DEC West European               | dec8_swedish_ci     |      1 |
| cp850    | DOS West European               | cp850_general_ci    |      1 |
| hp8      | HP West European                | hp8_english_ci      |      1 |
| koi8r    | KOI8-R Relcom Russian           | koi8r_general_ci    |      1 |
| latin1   | cp1252 West European            | latin1_swedish_ci   |      1 |
| latin2   | ISO 8859-2 Central European     | latin2_general_ci   |      1 |
| swe7     | 7bit Swedish                    | swe7_swedish_ci     |      1 |
| ascii    | US ASCII                        | ascii_general_ci    |      1 |
| ujis     | EUC-JP Japanese                 | ujis_japanese_ci    |      3 |
| sjis     | Shift-JIS Japanese              | sjis_japanese_ci    |      2 |
| hebrew   | ISO 8859-8 Hebrew               | hebrew_general_ci   |      1 |
| tis620   | TIS620 Thai                     | tis620_thai_ci      |      1 |
| euckr    | EUC-KR Korean                   | euckr_korean_ci     |      2 |
| koi8u    | KOI8-U Ukrainian                | koi8u_general_ci    |      1 |
| gb2312   | GB2312 Simplified Chinese       | gb2312_chinese_ci   |      2 |
| greek    | ISO 8859-7 Greek                | greek_general_ci    |      1 |
| cp1250   | Windows Central European        | cp1250_general_ci   |      1 |
| gbk      | GBK Simplified Chinese          | gbk_chinese_ci      |      2 |
| latin5   | ISO 8859-9 Turkish              | latin5_turkish_ci   |      1 |
| armscii8 | ARMSCII-8 Armenian              | armscii8_general_ci |      1 |
| utf8     | UTF-8 Unicode                   | utf8_general_ci     |      3 |
| ucs2     | UCS-2 Unicode                   | ucs2_general_ci     |      2 |
| cp866    | DOS Russian                     | cp866_general_ci    |      1 |
| keybcs2  | DOS Kamenicky Czech-Slovak      | keybcs2_general_ci  |      1 |
| macce    | Mac Central European            | macce_general_ci    |      1 |
| macroman | Mac West European               | macroman_general_ci |      1 |
| cp852    | DOS Central European            | cp852_general_ci    |      1 |
| latin7   | ISO 8859-13 Baltic              | latin7_general_ci   |      1 |
| utf8mb4  | UTF-8 Unicode                   | utf8mb4_general_ci  |      4 |
| cp1251   | Windows Cyrillic                | cp1251_general_ci   |      1 |
| utf16    | UTF-16 Unicode                  | utf16_general_ci    |      4 |
| utf16le  | UTF-16LE Unicode                | utf16le_general_ci  |      4 |
| cp1256   | Windows Arabic                  | cp1256_general_ci   |      1 |
| cp1257   | Windows Baltic                  | cp1257_general_ci   |      1 |
| utf32    | UTF-32 Unicode                  | utf32_general_ci    |      4 |
| binary   | Binary pseudo charset           | binary              |      1 |
| geostd8  | GEOSTD8 Georgian                | geostd8_general_ci  |      1 |
| cp932    | SJIS for Windows Japanese       | cp932_japanese_ci   |      2 |
| eucjpms  | UJIS for Windows Japanese       | eucjpms_japanese_ci |      3 |
| gb18030  | China National Standard GB18030 | gb18030_chinese_ci  |      4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.00 sec)

[mysqld]
character-set-server=utf8

show engines\G

*************************** 1. row ***************************
      Engine: InnoDB
     Support: DEFAULT
     Comment: Supports transactions, row-level locking, and foreign keys
Transactions: YES
          XA: YES
  Savepoints: YES
*************************** 2. row ***************************
      Engine: MRG_MYISAM
     Support: YES
     Comment: Collection of identical MyISAM tables
Transactions: NO
          XA: NO
  Savepoints: NO
*************************** 3. row ***************************
      Engine: MEMORY
     Support: YES
     Comment: Hash based, stored in memory, useful for temporary tables
Transactions: NO
          XA: NO
  Savepoints: NO
*************************** 4. row ***************************
      Engine: BLACKHOLE
     Support: YES
     Comment: /dev/null storage engine (anything you write to it disappears)
Transactions: NO
          XA: NO
  Savepoints: NO
*************************** 5. row ***************************
      Engine: MyISAM
     Support: YES
     Comment: MyISAM storage engine
Transactions: NO
          XA: NO
  Savepoints: NO
*************************** 6. row ***************************
      Engine: CSV
     Support: YES
     Comment: CSV storage engine
Transactions: NO
          XA: NO
  Savepoints: NO
*************************** 7. row ***************************
      Engine: ARCHIVE
     Support: YES
     Comment: Archive storage engine
Transactions: NO
          XA: NO
  Savepoints: NO
*************************** 8. row ***************************
      Engine: PERFORMANCE_SCHEMA
     Support: YES
     Comment: Performance Schema
Transactions: NO
          XA: NO
  Savepoints: NO
*************************** 9. row ***************************
      Engine: FEDERATED
     Support: NO
     Comment: Federated MySQL storage engine
Transactions: NULL
          XA: NULL
  Savepoints: NULL
9 rows in set (0.00 sec)

? data types

You asked for help about help category: "Data Types"
For more information, type 'help <item>', where <item> is one of the following
topics:
   AUTO_INCREMENT
   BIGINT
   BINARY
   BIT
   BLOB
   BLOB DATA TYPE
   BOOLEAN
   CHAR
   CHAR BYTE
   DATE
   DATETIME
   DEC
   DECIMAL
   DOUBLE
   DOUBLE PRECISION
   ENUM
   FLOAT
   INT
   INTEGER
   LONGBLOB
   LONGTEXT
   MEDIUMBLOB
   MEDIUMINT
   MEDIUMTEXT
   SET DATA TYPE
   SMALLINT
   TEXT
   TIME
   TIMESTAMP
   TINYBLOB
   TINYINT
   TINYTEXT
   VARBINARY
   VARCHAR
   YEAR DATA TYPE

? varchar

Name: 'VARCHAR'
Description:
[NATIONAL] VARCHAR(M) [CHARACTER SET charset_name] [COLLATE
collation_name]

A variable-length string. M represents the maximum column length in
characters. The range of M is 0 to 65,535. The effective maximum length
of a VARCHAR is subject to the maximum row size (65,535 bytes, which is
shared among all columns) and the character set used. For example, utf8
characters can require up to three bytes per character, so a VARCHAR
column that uses the utf8 character set can be declared to be a maximum
of 21,844 characters. See
http://dev.mysql.com/doc/refman/5.7/en/column-count-limit.html.

MySQL stores VARCHAR values as a 1-byte or 2-byte length prefix plus
data. The length prefix indicates the number of bytes in the value. A
VARCHAR column uses one length byte if values require no more than 255
bytes, two length bytes if values may require more than 255 bytes.

*Note*:

MySQL follows the standard SQL specification, and does not remove
trailing spaces from VARCHAR values.

VARCHAR is shorthand for CHARACTER VARYING. NATIONAL VARCHAR is the
standard SQL way to define that a VARCHAR column should use some
predefined character set. MySQL uses utf8 as this predefined character
set. http://dev.mysql.com/doc/refman/5.7/en/charset-national.html.
NVARCHAR is shorthand for NATIONAL VARCHAR.

URL: http://dev.mysql.com/doc/refman/5.7/en/string-type-overview.html

-- 插入学院数据
insert into tb_college (collname, collintro) values 
('计算机学院', '创建于1956年是我国首批建立计算机专业。学院现有计算机科学与技术一级学科和网络空间安全一级学科博士学位授予权，其中计算机科学与技术一级学科具有博士后流动站。计算机科学与技术一级学科在2017年全国第四轮学科评估中评为A；2019 U.S.News全球计算机学科排名26名；ESI学科排名0.945‰，进入全球前1‰，位列第43位。'),
('外国语学院', '1998年浙江大学、杭州大学、浙江农业大学、浙江医科大学四校合并，成立新的浙江大学。1999年原浙江大学外语系、原杭州大学外国语学院、原杭州大学大外部、原浙江农业大学公外部、原浙江医科大学外语教学部合并，成立浙江大学外国语学院。2003年学院更名为浙江大学外国语言文化与国际交流学院。'),
('经济管理学院', '四川大学经济学院历史悠久、传承厚重，其前身是创办于1905年的四川大学经济科,距今已有100多年的历史。已故著名经济学家彭迪先、张与九、蒋学模、胡寄窗、陶大镛、胡代光，以及当代著名学者刘诗白等曾先后在此任教或学习。在长期的办学过程中，学院坚持以马克思主义的立场、观点、方法为指导，围绕建设世界一流经济学院的奋斗目标，做实“两个伟大”深度融合，不断提高党的建设质量与科学推进一流事业深度融合。');

-- 插入学生数据
insert into tb_student (stuid, stuname, stusex, stubirth, stuaddr, collid) values
(1001, '杨逍', 1, '1990-3-4', '四川成都', 1),
(1002, '任我行', 1, '1992-2-2', '湖南长沙', 1),
(1033, '王语嫣', 0, '1989-12-3', '四川成都', 1),
(1572, '岳不群', 1, '1993-7-19', '陕西咸阳', 1),
(1378, '纪嫣然', 0, '1995-8-12', '四川绵阳', 1),
(1954, '林平之', 1, '1994-9-20', '福建莆田', 1),
(2035, '东方不败', 1, '1988-6-30', null, 2),
(3011, '林震南', 1, '1985-12-12', '福建莆田', 3),
(3755, '项少龙', 1, '1993-1-25', null, 3),
(3923, '杨不悔', 0, '1985-4-17', '四川成都', 3),
(4040, '隔壁老王', 1, '1989-1-1', '四川成都', 2);

-- 删除学生数据
delete from tb_student where stuid=4040;

-- 更新学生数据
update tb_student set stuname='杨过', stuaddr='湖南长沙' where stuid=1001;

-- 插入老师数据
insert into tb_teacher (teaid, teaname, teatitle, collid) values 
(1122, '张三丰', '教授', 1),
(1133, '宋远桥', '副教授', 1),
(1144, '杨逍', '副教授', 1),
(2255, '范遥', '副教授', 2),
(3366, '韦一笑', '讲师', 3);

-- 插入课程数据
insert into tb_course (couid, couname, coucredit, teaid) values 
(1111, 'Python程序设计', 3, 1122),
(2222, 'Web前端开发', 2, 1122),
(3333, '操作系统', 4, 1122),
(4444, '计算机网络', 2, 1133),
(5555, '编译原理', 4, 1144),
(6666, '算法和数据结构', 3, 1144),
(7777, '经贸法语', 3, 2255),
(8888, '成本会计', 2, 3366),
(9999, '审计学', 3, 3366);

-- 插入选课数据
insert into tb_record (sid, cid, seldate, score) values 
(1001, 1111, '2017-09-01', 95),
(1001, 2222, '2017-09-01', 87.5),
(1001, 3333, '2017-09-01', 100),
(1001, 4444, '2018-09-03', null),
(1001, 6666, '2017-09-02', 100),
(1002, 1111, '2017-09-03', 65),
(1002, 5555, '2017-09-01', 42),
(1033, 1111, '2017-09-03', 92.5),
(1033, 4444, '2017-09-01', 78),
(1033, 5555, '2017-09-01', 82.5),
(1572, 1111, '2017-09-02', 78),
(1378, 1111, '2017-09-05', 82),
(1378, 7777, '2017-09-02', 65.5),
(2035, 7777, '2018-09-03', 88),
(2035, 9999, default, null),
(3755, 1111, default, null),
(3755, 8888, default, null),
(3755, 9999, '2017-09-01', 92);

-- 查询所有学生信息
select * from tb_student;

-- 查询所有课程名称及学分(投影和别名)
select couname, coucredit from tb_course;
select couname as 课程名称, coucredit as 学分 from tb_course;

-- 查询所有学生的姓名和性别(条件运算)
select stuname as 姓名, case stusex when 1 then '男' else '女' end as 性别 from tb_student;
select stuname as 姓名, if(stusex, '男', '女') as 性别 from tb_student;

-- 查询所有女学生的姓名和出生日期(筛选)
select stuname, stubirth from tb_student where stusex=0;

-- 查询所有80后学生的姓名、性别和出生日期(筛选)
select stuname, stusex, stubirth from tb_student where stubirth>='1980-1-1' and stubirth<='1989-12-31';
select stuname, stusex, stubirth from tb_student where stubirth between '1980-1-1' and '1989-12-31';

-- 查询姓"杨"的学生姓名和性别(模糊)
select stuname, stusex from tb_student where stuname like '杨%';

-- 查询姓"杨"名字两个字的学生姓名和性别(模糊)
select stuname, stusex from tb_student where stuname like '杨_';

-- 查询姓"杨"名字三个字的学生姓名和性别(模糊)
select stuname, stusex from tb_student where stuname like '杨__';

-- 查询名字中有"不"字或"嫣"字的学生的姓名(模糊)
select stuname, stusex from tb_student where stuname like '%不%' or stuname like '%嫣%';

-- 查询没有录入家庭住址的学生姓名(空值)
select stuname from tb_student where stuaddr is null;

-- 查询录入了家庭住址的学生姓名(空值)
select stuname from tb_student where stuaddr is not null;

-- 查询学生选课的所有日期(去重)
select distinct seldate from tb_record;

-- 查询学生的家庭住址(去重)
select distinct stuaddr from tb_student where stuaddr is not null;

-- 查询男学生的姓名和生日按年龄从大到小排列(排序)
select stuname as 姓名, datediff(curdate(), stubirth) div 365 as 年龄 from tb_student where stusex=1 order by 年龄 desc;

-- 查询年龄最大的学生的出生日期(聚合函数)
select min(stubirth) from tb_student;

-- 查询年龄最小的学生的出生日期(聚合函数)
select max(stubirth) from tb_student;

-- 查询男女学生的人数(分组和聚合函数)
select stusex, count(*) from tb_student group by stusex;

-- 查询课程编号为1111的课程的平均成绩(筛选和聚合函数)
select avg(score) from tb_record where cid=1111;

-- 查询学号为1001的学生所有课程的平均分(筛选和聚合函数)
select avg(score) from tb_record where sid=1001;

-- 查询每个学生的学号和平均成绩(分组和聚合函数)
select sid as 学号, avg(score) as 平均分 from tb_record group by sid;

-- 查询平均成绩大于等于90分的学生的学号和平均成绩
-- 分组以前的筛选使用where子句 / 分组以后的筛选使用having子句
select sid as 学号, avg(score) as 平均分 from tb_record group by sid having 平均分>=90;

-- 查询年龄最大的学生的姓名(子查询/嵌套的查询)
select stuname from tb_student where stubirth=( select min(stubirth) from tb_student );

-- 查询年龄最大的学生姓名和年龄(子查询+运算)
select stuname as 姓名, datediff(curdate(), stubirth) div 365 as 年龄 from tb_student where stubirth=( select min(stubirth) from tb_student );

-- 查询选了两门以上的课程的学生姓名(子查询/分组条件/集合运算)
select stuname from tb_student where stuid in ( select stuid from tb_record group by stuid having count(stuid)>2 );

-- 查询学生姓名、课程名称以及成绩(连接查询)
select stuname, couname, score from tb_student t1, tb_course t2, tb_record t3 where stuid=sid and couid=cid and score is not null;

-- 查询学生姓名、课程名称以及成绩按成绩从高到低查询第11-15条记录(内连接+分页)
select stuname, couname, score from tb_student inner join tb_record on stuid=sid inner join tb_course on couid=cid where score is not null order by score desc limit 5 offset 10;

select stuname, couname, score from tb_student inner join tb_record on stuid=sid inner join tb_course on couid=cid where score is not null order by score desc limit 10, 5;

-- 查询选课学生的姓名和平均成绩(子查询和连接查询)
select stuname, avgmark from tb_student, ( select sid, avg(score) as avgmark from tb_record group by sid ) temp where stuid=sid;

select stuname, avgmark from tb_student inner join ( select sid, avg(score) as avgmark from tb_record group by sid ) temp on stuid=sid;

-- 查询每个学生的姓名和选课数量(左外连接和子查询)
select stuname, ifnull(total, 0) from tb_student left outer join ( select sid, count(sid) as total from tb_record group by sid ) temp on stuid=sid;

-- 创建可以远程登录的root账号并为其指定口令
create user 'root'@'%' identified by '123456';

-- 为远程登录的root账号授权操作所有数据库所有对象的所有权限并允许其将权限再次赋予其他用户
grant all privileges on *.* to 'root'@'%' with grant option;

-- 创建名为hellokitty的用户并为其指定口令
create user 'hellokitty'@'%' identified by '123123';

-- 将对school数据库所有对象的所有操作权限授予hellokitty
grant all privileges on school.* to 'hellokitty'@'%';

-- 召回hellokitty对school数据库所有对象的insert/delete/update权限
revoke insert, delete, update on school.* from 'hellokitty'@'%';

explain select * from tb_student where stuname='林震南'\G

*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: tb_student
   partitions: NULL
         type: ALL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: 11
     filtered: 10.00
        Extra: Using where
1 row in set, 1 warning (0.00 sec)

create index idx_student_name on tb_student(stuname);

explain select * from tb_student where stuname='林震南'\G

*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: tb_student
   partitions: NULL
         type: ref
possible_keys: idx_student_name
          key: idx_student_name
      key_len: 62
          ref: const
         rows: 1
     filtered: 100.00
        Extra: NULL
1 row in set, 1 warning (0.00 sec)

create index idx_student_name_1 on tb_student(stuname(1));

explain select * from tb_student where stuname='林震南'\G

*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: tb_student
   partitions: NULL
         type: ref
possible_keys: idx_student_name
          key: idx_student_name
      key_len: 5
          ref: const
         rows: 2
     filtered: 100.00
        Extra: Using where
1 row in set, 1 warning (0.00 sec)

alter table tb_student drop index idx_student_name;

drop index idx_student_name on tb_student;

create view vw_avg_score 
as 
    select sid, round(avg(score), 1) as avgscore 
    from tb_record group by sid;

create view vw_student_score 
as 
    select stuname, avgscore 
    from tb_student, vw_avg_score 
    where stuid=sid;

select stuname, avgscore from vw_student_score order by avgscore desc;

+--------------+----------+
| stuname      | avgscore |
+--------------+----------+
| 杨过         |     95.6 |
| 任我行       |     53.5 |
| 王语嫣       |     84.3 |
| 纪嫣然       |     73.8 |
| 岳不群       |     78.0 |
| 东方不败     |     88.0 |
| 项少龙       |     92.0 |
+--------------+----------+

drop view vw_student_score;

drop procedure if exists sp_score_by_cid;

delimiter $$

create procedure sp_score_by_cid(
	courseId int, 
	out maxScore decimal(4,1), 
	out minScore decimal(4,1),
	out avgScore decimal(4,1)
)
begin
	select max(score) into maxScore from tb_record 
		where cid=courseId;
	select min(score) into minScore from tb_record 
		where cid=courseId;
	select avg(score) into avgScore from tb_record 
		where cid=courseId;
end $$

delimiter ;

call sp_score_by_cid(1111, @a, @b, @c);
select @a, @b, @c;

call sp_score_by_cid(1111, @a, @b, @c);

select @a as 最高分, @b as 最低分, @c as 平均分;

drop procedure sp_score_by_cid;