mysql

数据库类型

系型数据库：数据存放在硬盘中
- MySQL（5.7之前都是开源的、8.0开始商业化）
- mariadb（从10.0版本开始）
- MSsql
- oracle（商业软件）
- sqlserver
nosql非关系型数据库：数据存放在内存中、变量形式、key=value
- mongodb
- redis
- memcache

数据库管理系统

数据库管理系统（Database Management System，简称DBMS）是为管理数据库而设计的电脑软件系统，一般具有存储、截取、安全保障、备份等基础功能

管理关系型数据库的系统叫做：关系型数据库管理系统(Relational Database Management System，简称RDBMS)

关系型数据库的常见组件

数据库	database
表	table，由行（row）和列（column）组成
索引	index
视图	view
用户	user
权限	privilege
存储过程	procedure
存储函数	function
触发器	trigger
事件调度器	event scheduler

SQL语句

SQL语句类型	对应操作
DDL	CREATE：创建 DROP：删除 ALTER：修改
DML	INSERT：向表中插入数据 DELETE：删除表中数据 UPDATE：更新表中数据 SELECT：查询表中数据
DCL	GRANT：授权 REVOKE：移除授权

mysql数据类型

数值类型

日期和时间类型

字符串类型

mysql安装与配置

mysql安装

mysql安装方式有三种：

源代码：编译安装
二进制格式的程序包：展开至特定路径，并经过简单配置后即可使用
程序包管理器管理的程序包：
- rpm：有两种
  - OS Vendor：操作系统发行商提供的
  - 项目官方提供的
- deb

//配置mysql的yum源
http://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm
rpm -Uvh /usr/src/mysql57-community-release-el7-11.noarch.rpm
//禁用mysql
yum module disable mysql
//安装mysql5.7
yum -y install mysql-community-server mysql-community-client 
mysql-community-common mysql-community-devel  --nogpgcheck

mysql配置

//启动mysql并设置开机自动启动
systemctl enable --now mysqld
systemctl status mysqld

//查看3306端口已经监听起来
[root@z1 ~]# ss -antl            
LISTEN  0       80                    *:3306                *:*   

//在日志文件中找出临时密码  
[root@z1 ~]# grep "password" /var/log/mysqld.log
2022-07-25T09:44:58.856633Z 1 [Note] A temporary password is generated for root@localhost: Nt(G=u7vTl2<

//使用获取到的临时密码登录mysql
[root@z1 ~]# mysql -uroot -p
Enter password:        //把临时密码输入
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.38

Copyright (c) 2000, 2022, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

//修改mysql登录密码
mysql> set global validate_password_policy=0;
Query OK, 0 rows affected (0.00 sec)

mysql> set global validate_password_length=1;
Query OK, 0 rows affected (0.00 sec)

mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'zhangdezhi123!';
Query OK, 0 rows affected (0.01 sec)

mysql 基本操作

mysql工具使用

mysql
-u 指定用户名，默认为root
-h 指定服务器主机，默认为localhost，推荐使用ip地址
-p 指定用户的密码
-P# 指定数据库监听的端口，这里的#需用实际的端口号代替，如-P3307
-V 查看当前使用的mysql版本
-e 不登录mysql执行sql语句后退出，常用于脚本

DDL操作

数据库操作

//创建数据库
mysql> create database zdz;
Query OK, 1 row affected (0.00 sec)
//查看当前实例有哪些数据库
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| zdz                |
+--------------------+
5 rows in set (0.00 sec)
//删除数据库
mysql> drop database zdz;
Query OK, 0 rows affected (0.01 sec)

表操作

//创建一个数据库
mysql> create database zdz;
Query OK, 1 row affected (0.00 sec)
//进入数据库
mysql> use zdz;
Database changed
//创建表
mysql> create table zdz(id int not null,name varchar(10) not null,age tinyint
);
Query OK, 0 rows affected (0.01 sec)
查看当前数据库有哪些表
mysql> show tables;
+---------------+
| Tables_in_zdz |
+---------------+
| zdz           |
+---------------+
1 row in set (0.00 sec)
//删除表
mysql> drop table zdz;
Query OK, 0 rows affected (0.00 sec)

mysql> show tables;
Empty set (0.01 sec)

用户操作

mysql用户帐号由两部分组成，如'USERNAME'@'HOST'，表示此USERNAME只能从此HOST上远程登录
这里（'USERNAME'@'HOST'）的HOST用于限制此用户可通过哪些主机远程连接mysql程序，其值可为：
- IP地址，如：172.16.12.129
- 通配符
  - %：匹配任意长度的任意字符，常用于设置允许从任何主机登录
  - _：匹配任意单个字符

//数据库用户创建
mysql>  create user 'zdz'@'127.0.0.1' identified by 'zhangdezhi123!';
Query OK, 0 rows affected (0.00 sec)

mysql> quit
Bye
//使用新创建的用户和密码登录
[root@z1 ~]# mysql -uzdz -p -h127.0.0.1
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.38 MySQL Community Server (GPL)

Copyright (c) 2000, 2022, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.


//删除数据库用户
mysql> drop user 'zdz'@'127.0.0.1';
Query OK, 0 rows affected (0.00 sec)
//查看用户以及可登录主机
mysql> select user,host from mysql.user;
+---------------+-----------+
| user          | host      |
+---------------+-----------+
| mysql.session | localhost |
| mysql.sys     | localhost |
| root          | localhost |
+---------------+-----------+
3 rows in set (0.00 sec)

查看命令SHOW

//查看支持的所有字符集
mysql> 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 |
......

//查看当前数据库支持的所有存储引擎
mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                        | Transactions | XA   | Savepoints |
......

//不进入某数据库而列出其包含的所有表
mysql> show tables from zdz;
Empty set (0.00 sec)

//查看表结构
mysql> desc zdz.zdz;
+-------+--------------+------+-----+---------+-------+
| Field | Type         | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| id    | int(11)      | NO   |     | NULL    |       |
| name  | varchar(100) | NO   |     | NULL    |       |
| age   | tinyint(4)   | YES  |     | NULL    |       |
+-------+--------------+------+-----+---------+-------+
3 rows in set (0.01 sec)

//查看某表的创建命令
mysql> desc zdz.zdz;
+-------+--------------+------+-----+---------+-------+
| Field | Type         | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| id    | int(11)      | NO   |     | NULL    |       |
| name  | varchar(100) | NO   |     | NULL    |       |
| age   | tinyint(4)   | YES  |     | NULL    |       |
+-------+--------------+------+-----+---------+-------+
3 rows in set (0.01 sec)

mysql> show create table zdz.zdz;
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                         |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------+
| zdz   | CREATE TABLE `zdz` (
  `id` int(11) NOT NULL,
  `name` varchar(100) NOT NULL,
  `age` tinyint(4) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)


//查看某表的状态
mysql> SHOW TABLE STATUS LIKE 'zdz'\G
*************************** 1. row ***************************
           Name: zdz
         Engine: InnoDB
        Version: 10
     Row_format: Dynamic
           Rows: 0
 Avg_row_length: 0
    Data_length: 16384
Max_data_length: 0
   Index_length: 0
      Data_free: 0
 Auto_increment: NULL
    Create_time: 2022-07-26 06:30:43
    Update_time: NULL
     Check_time: NULL
      Collation: latin1_swedish_ci
       Checksum: NULL
 Create_options: 
        Comment: 
1 row in set (0.00 sec)

获取帮助

//语法：HELP keyword;
mysql> help create table;   //获取创建表的帮助
Name: 'CREATE TABLE'
Description:
Syntax:
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    (create_definition,...)
    [table_options]
    [partition_options]

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    [(create_definition,...)]
    [table_options]
    [partition_options]
    [IGNORE | REPLACE]
    [AS] query_expression

DML操作

DML操作包括增(INSERT)、删(DELETE)、改(UPDATE)、查(SELECT)，均属针对表的操作。

INSERT语句

//语法：INSERT [INTO] table_name [(column_name,...)] {VALUES | VALUE} (value1,...),(...),...
mysql> insert zdz(id,name,age) values(4,'zhangsan',18),(5,'qq',null);
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

SELECT语句

字段column表示法

表示符	代表什么？
*	所有字段
as	字段别名，如col1 AS alias1 当表名很长时用别名代替

条件判断语句where

操作类型	常用操作符
操作符	>，<，>=，<=，=，!= BETWEEN column# AND column# LIKE：模糊匹配 RLIKE：基于正则表达式进行模式匹配 IS NOT NULL：非空 IS NULL：空
条件逻辑操作	AND OR NOT

ORDER BY：排序，默认为升序（ASC）

ORDER BY语句	意义
ORDER BY ‘column_name'	根据column_name进行升序排序
ORDER BY 'column_name' DESC	根据column_name进行降序排序
ORDER BY ’column_name' LIMIT 2	根据column_name进行升序排序并只取前2个结果
ORDER BY ‘column_name' LIMIT 1,2	根据column_name进行升序排序并且略过第1个结果取后面的2个结果

//语法：SELECT column1,column2,... FROM table_name [WHERE clause] [ORDER BY 'column_name' [DESC]] [LIMIT [m,]n];
mysql> select * from zdz;
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   20 |
|  2 | lisi     |   18 |
|  3 | wangwu   |   22 |
|  4 | zhangsan |   18 |
|  5 | qq       | NULL |
+----+----------+------+
5 rows in set (0.00 sec)

mysql> select name from zdz;     //只看name字段
+----------+
| name     |
+----------+
| zhangsan |
| lisi     |
| wangwu   |
| zhangsan |
| qq       |
+----------+
5 rows in set (0.00 sec)

mysql> select * from zdz order by age;  //根据age字段升序
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  5 | qq       | NULL |
|  2 | lisi     |   18 |
|  4 | zhangsan |   18 |
|  1 | zhangsan |   20 |
|  3 | wangwu   |   22 |
+----+----------+------+
5 rows in set (0.00 sec)

mysql> select * from zdz order by age desc;  //根据age字段降序
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  3 | wangwu   |   22 |
|  1 | zhangsan |   20 |
|  2 | lisi     |   18 |
|  4 | zhangsan |   18 |
|  5 | qq       | NULL |
+----+----------+------+
5 rows in set (0.01 sec)

mysql> select * from zdz order by age desc limit 2;  //根据age字段降序只取前二个结果
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  3 | wangwu   |   22 |
|  1 | zhangsan |   20 |
+----+----------+------+
2 rows in set (0.00 sec)

mysql> select * from zdz order by age desc limit 1,2; 
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   20 |
|  2 | lisi     |   18 |
+----+----------+------+
2 rows in set (0.00 sec)

mysql> select * from zdz where age  >=20;
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   20 |
|  3 | wangwu   |   22 |
+----+----------+------+
2 rows in set (0.00 sec)

mysql> select * from zdz where age  >=20 and name = 'zhangsan';
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   20 |
+----+----------+------+
1 row in set (0.00 sec)

mysql> select * from zdz where age between 18 and 20;
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   20 |
|  2 | lisi     |   18 |
|  4 | zhangsan |   18 |
+----+----------+------+
3 rows in set (0.00 sec)

mysql> select * from zdz where age is not null;
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   20 |
|  2 | lisi     |   18 |
|  3 | wangwu   |   22 |
|  4 | zhangsan |   18 |
+----+----------+------+
4 rows in set (0.00 sec)

mysql> select * from zdz where age is  null;
+----+------+------+
| id | name | age  |
+----+------+------+
|  5 | qq   | NULL |
+----+------+------+
1 row in set (0.00 sec)

update语句

//语法：UPDATE table_name SET column1 = new_value1[,column2 = new_value2,...] [WHERE clause] [ORDER BY 'column_name' [DESC]] [LIMIT [m,]n];

mysql> update zdz  set age = 18 where name = 'qq';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from zdz;
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   30 |
|  2 | lisi     |   30 |
|  3 | wangwu   |   30 |
|  4 | zhangsan |   30 |
|  5 | qq       |   18 |
+----+----------+------+
5 rows in set (0.00 sec)

delete语句

//语法：DELETE FROM table_name [WHERE clause] [ORDER BY 'column_name' [DESC]] [LIMIT [m,]n];
mysql> select * from zdz;
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   30 |
|  2 | lisi     |   30 |
|  3 | wangwu   |   30 |
|  4 | zhangsan |   30 |
|  5 | qq       |   18 |
+----+----------+------+
5 rows in set (0.00 sec)

mysql> delete from zdz where id = 5;      //删除一个字段
Query OK, 1 row affected (0.00 sec)

mysql> select * from zdz;            //删除整张表的内容
+----+----------+------+
| id | name     | age  |
+----+----------+------+
|  1 | zhangsan |   30 |
|  2 | lisi     |   30 |
|  3 | wangwu   |   30 |
|  4 | zhangsan |   30 |
+----+----------+------+
4 rows in set (0.00 sec)

mysql> desc zdz;           
+-------+--------------+------+-----+---------+-------+
| Field | Type         | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| id    | int(11)      | NO   |     | NULL    |       |
| name  | varchar(100) | NO   |     | NULL    |       |
| age   | tinyint(4)   | YES  |     | NULL    |       |
+-------+--------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

truncate语句

truncate与delete的区别：

语句类型	特点
删除	DELETE删除表内容时仅删除内容，但会保留表结构 DELETE语句每次删除一行，并在事务日志中为所删除的每行记录一项可以通过回滚事务日志恢复数据非常占用空间
截断	删除表中所有数据，且无法恢复表结构、约束和索引等保持不变，新添加的行计数值重置为初始值执行速度比DELETE快，且使用的系统和事务日志资源少

mysql> select * from zdz;
+----+-----------+------+
| id | name      | age  |
+----+-----------+------+
|  2 | jerry     |   23 |
|  3 | wangqing  |   25 |
|  4 | sean      |   28 |
|  5 | zhangshan |   26 |
|  6 | zhangshan |   20 |
|  7 | lisi      | NULL |
|  1 | z         |   20 |
+----+-----------+------+
7 rows in set (0.00 sec)

mysql> truncate zdz;
Query OK, 0 rows affected (0.00 sec)

DCL操作

创建授权grant

权限类型	代表什么？
ALL	所有权限
SELECT	读取内容的权限
INSERT	插入内容的权限
UPDATE	更新内容的权限
DELETE	删除内容的权限

表示方式	意义
*	所有库的所有表
db_name	指定库的所有表
db_name.table_name	指定库的指定表

WITH GRANT OPTION：被授权的用户可将自己的权限副本转赠给其他用户,不建议使用。

//语法GRANT priv_type,... ON [object_type] db_name.table_name TO ‘username'@'host' [IDENTIFIED BY 'password'] [WITH GRANT OPTION];
//授权zdz用户在数据库本机上登录访问所有数据库
mysql> grant all on *.* to 'zdz'@'localhost' identified by 'Jjking123!';
Query OK, 0 rows affected, 1 warning (0.00 sec)
[root@z1 ~]# mysql -uzdz -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 3

mysql> 
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| jjk                |
| mysql              |
| performance_schema |
| sys                |
| zdz                |
+--------------------+
6 rows in set (0.00 sec)

mysql> drop database jjk;
Query OK, 0 rows affected (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| zdz                |
+--------------------+
5 rows in set (0.00 sec)

mysql> grant all on *.* to 'root'@'192.168.26.1' identified by 'Zhangdezhi123!';
Query OK, 0 rows affected, 1 warning (0.00 sec)

posted @ 2022-07-25 22:43 世界的尽头* 阅读(40) 评论(0) 收藏举报

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