1、配置YUM源
在MySQL官网中下载YUM源rpm安装包：http://dev.mysql.com/downloads/repo/yum/
# 下载mysql源安装包
shell> wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm
# 安装mysql源
shell> yum localinstall mysql57-community-release-el7-8.noarch.rpm
检查mysql源是否安装成功
shell> yum repolist enabled | grep "mysql.*-community.*"
看到上图所示表示安装成功。可以修改vim /etc/yum.repos.d/mysql-community.repo源，改变默认安装的mysql版本。比如要安装5.6版本，将5.7源的enabled=1改成enabled=0。然后再将5.6源的enabled=0改成enabled=1即可。改完之后的效果如下所示：
2、安装MySQL
shell> yum install mysql-community-server
如果安装提示出错，将对应版本的enabled=0改为enabled=1，再次安装即可
3、启动MySQL服务
shell> systemctl start mysqld
查看MySQL的启动状态
shell> systemctl status mysqld
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; disabled; vendor preset: disabled)
Active: active (running) since 五 2016-06-24 04:37:37 CST; 35min ago
Main PID: 2888 (mysqld)
CGroup: /system.slice/mysqld.service
└─2888 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
6月24 04:37:36 localhost.localdomain systemd[1]: Starting MySQL Server...
6月24 04:37:37 localhost.localdomain systemd[1]: Started MySQL Server.
4、开机启动
shell> systemctl enable mysqld
shell> systemctl daemon-reload
5、修改root本地登录密码
mysql安装完成之后，在/var/log/mysqld.log文件中给root生成了一个默认密码。通过下面的方式找到root默认密码，然后登录mysql进行修改：
shell> grep 'temporary password' /var/log/mysqld.log
shell> mysql -uroot -p
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!';
或者
mysql> set password for 'root'@'localhost'=password('MyNewPass4!');
注意：mysql5.7默认安装了密码安全检查插件（validate_password），默认密码检查策略要求密码必须包含：大小写字母、数字和特殊符号，并且长度不能少于8位。否则会提示ERROR 1819 (HY000): Your password does not satisfy the current policy requirements错误，如下图所示：
通过msyql环境变量可以查看密码策略的相关信息：
mysql> show variables like '%password%';
validate_password_policy：密码策略，默认为MEDIUM策略 validate_password_dictionary_file：密码策略文件，策略为STRONG才需要 validate_password_length：密码最少长度 validate_password_mixed_case_count：大小写字符长度，至少1个 validate_password_number_count：数字至少1个 validate_password_special_char_count：特殊字符至少1个 上述参数是默认策略MEDIUM的密码检查规则。
共有以下几种密码策略：
策略 检查规则
0 or LOW Length
1 or MEDIUM Length; numeric, lowercase/uppercase, and special characters
2 or STRONG Length; numeric, lowercase/uppercase, and special characters; dictionary file
MySQL官网密码策略详细说明：http://dev.mysql.com/doc/refman/5.7/en/validate-password-options-variables.html#sysvar_validate_password_policy
修改密码策略
在/etc/my.cnf文件添加validate_password_policy配置，指定密码策略
# 选择0（LOW），1（MEDIUM），2（STRONG）其中一种，选择2需要提供密码字典文件
validate_password_policy=0
如果不需要密码策略，添加my.cnf文件中添加如下配置禁用即可：
validate_password = off
重新启动mysql服务使配置生效：
systemctl restart mysqld
6、添加远程登录用户
默认只允许root帐户在本地登录，如果要在其它机器上连接mysql，必须修改root允许远程连接，或者添加一个允许远程连接的帐户，为了安全起见，我添加一个新的帐户：
mysql> GRANT ALL PRIVILEGES ON *.* TO 'yangxin'@'%' IDENTIFIED BY 'Yangxin0917!' WITH GRANT OPTION;
7、配置默认编码为utf8
修改/etc/my.cnf配置文件，在[mysqld]下添加编码配置，如下所示：
[mysqld]
character_set_server=utf8
init_connect='SET NAMES utf8'
重新启动mysql服务，查看数据库默认编码如下所示：
默认配置文件路径： 配置文件：/etc/my.cnf日志文件：/var/log/var/log/mysqld.log服务启动脚本：/usr/lib/systemd/system/mysqld.servicesocket文件：/var/run/mysqld/mysqld.pid
用户权限操作
root查询所有用户
select user, host, authentication_string from mysql.user;
创建用户
create user <%username%>@<%host%> identified by <%password%>;
例如create user‘admin’@’%’ identified by ‘Password!’
删除用户
drop user <%username%>@<%host%> ;
授权
grant <%privileges%> on <%databasename%>.<%tablename%> to <%username%>@<%host%>;
例如：grant all on *.* to ‘admin’@’%’;
| Privilege | Context | Comment |
+-------------------------+---------------------------------------+-------------------------------------------------------+
| Alter | Tables | To alter the table |
| Alter routine | Functions,Procedures | To alter or drop stored functions/procedures |
| Create | Databases,Tables,Indexes | To create new databases and tables |
| Create routine | Databases | To use CREATE FUNCTION/PROCEDURE |
| Create temporary tables | Databases | To use CREATE TEMPORARY TABLE |
| Create view | Tables | To create new views |
| Create user | Server Admin | To create new users |
| Delete | Tables | To delete existing rows |
| Drop | Databases,Tables | To drop databases, tables, and views |
| Event | Server Admin | To create, alter, drop and execute events |
| Execute | Functions,Procedures | To execute stored routines |
| File | File access on server | To read and write files on the server |
| Grant option | Databases,Tables,Functions,Procedures | To give to other users those privileges you possess |
| Index | Tables | To create or drop indexes |
| Insert | Tables | To insert data into tables |
| Lock tables | Databases | To use LOCK TABLES (together with SELECT privilege) |
| Process | Server Admin | To view the plain text of currently executing queries |
| Proxy | Server Admin | To make proxy user possible |
| References | Databases,Tables | To have references on tables |
| Reload | Server Admin | To reload or refresh tables, logs and privileges |
| Replication client | Server Admin | To ask where the slave or master servers are |
| Replication slave | Server Admin | To read binary log events from the master |
| Select | Tables | To retrieve rows from table |
| Show databases | Server Admin | To see all databases with SHOW DATABASES |
| Show view | Tables | To see views with SHOW CREATE VIEW |
| Shutdown | Server Admin | To shut down the server |
| Super | Server Admin | To use KILL thread, SET GLOBAL, CHANGE MASTER, etc. |
| Trigger | Tables | To use triggers |
| Create tablespace | Server Admin | To create/alter/drop tablespaces |
| Update | Tables | To update existing rows |
| Usage | Server Admin | No privileges - allow connect only |
+-------------------------+---------------------------------------+-------------------------------------------------------+
数据库操作
删除数据库
drop database databasename;
创建数据库
create database databasename;
使用数据库
use databasename;
2 自增ID来自Flicker的解决方案
因为MySQL本身支持auto_increment操作，很自然地，我们会想到借助这个特性来实现这个功能。Flicker在解决全局ID生成方案里就采用了MySQL自增长ID的机制（auto_increment + replace into + MyISAM）。一个生成64位ID方案具体就是这样的： 先创建单独的数据库(eg:ticket)，然后创建一个表：
1 CREATE TABLE Tickets64 (
2 id bigint(20) unsigned NOT NULL auto_increment,
3 stub char(1) NOT NULL default '',
4 PRIMARY KEY (id),
5 UNIQUE KEY stub (stub)
6 ) ENGINE=MyISAM
当我们插入记录后，执行SELECT * from Tickets64，查询结果就是这样的：
+-------------------+------+| id | stub |+-------------------+------+| 72157623227190423 | a |+-------------------+------+在我们的应用端需要做下面这两个操作，在一个事务会话里提交：
1 REPLACE INTO Tickets64 (stub) VALUES ('a');
2 SELECT LAST_INSERT_ID();
这样我们就能拿到不断增长且不重复的ID了。 到上面为止，我们只是在单台数据库上生成ID，从高可用角度考虑，接下来就要解决单点故障问题：Flicker启用了两台数据库服务器来生成ID，通过区分auto_increment的起始值和步长来生成奇偶数的ID。
1 TicketServer1:
2 auto-increment-increment = 2
3 auto-increment-offset = 1
4
5 TicketServer2:
6 auto-increment-increment = 2
7 auto-increment-offset = 2
最后，在客户端只需要通过轮询方式取ID就可以了。
优点：充分借助数据库的自增ID机制，提供高可靠性，生成的ID有序。缺点：占用两个独立的MySQL实例，有些浪费资源，成本较高。
