一、mysql5.7 rpm 安装（单机）
一、下载需要的rpm包
mysql-community-client-5.7.26-1.el6.x86_64.rpm
mysql-community-common-5.7.26-1.el6.x86_64.rpm
mysql-community-libs-5.7.26-1.el6.x86_64.rpm
mysql-community-server-5.7.26-1.el6.x86_64.rpm
源码获取方式（免费）：
（1）登录-注册：http://resources.kittytiger.cn/
（2）签到获取积分
（3）搜索：mysql5.7安装包+单节点安装+主从安装--网盘
下载地址:http://ftp.ntu.edu.tw/MySQL/Downloads/MySQL-5.7/
二、查看之前有没有安装mysql有就卸载
查看：rpm -qa | grep -i mysql
删除之前所有mysql相关的东西
yum -y remove mysql*
注：如果卸载失败使用如下语句
查看：rpm -qa | grep -i mysql
卸载：rpm -e mysql-community-common-5.7.26-1.el6.x86_64 mysql-community-client-5.7.26-1.el6.x86_64 mysql-community-libs-5.7.26-1.el6.x86_64 mysql-community-server-5.7.26-1.el6.x86_64
三、安装mysql
将如下四个rpm包拷贝到/opt下
然后执行
cd /opt
yum install mysql-community-server-5.7.26-1.el6.x86_64.rpm mysql-community-client-5.7.26-1.el6.x86_64.rpm mysql-community-common-5.7.26-1.el6.x86_64.rpm mysql-community-libs-5.7.26-1.el6.x86_64.rpm
service mysqld start #启动mysql
service mysqld stop #关闭mysql
service mysqld status #状态
service mysqld restart #重启
启动失败就：
rm -fr /var/lib/mysql/*
rm /var/lock/subsys/mysqld
killall mysqld
四、设置密码
mysql5.7安装好后默认临时密码放在/var/log/mysqld.log里面了
[root@localhost ~]#grep 'temporary password' /var/log/mysqld.log
[root@master51 mha-soft-student]# mysql -uroot -p"N%;j+r!!s0pr"
可以使用临时密码第一次登陆 mysql
注：如果临时密码里有！这样的字符，就重新初始化数据库，换一个新的初始密码
第一次登陆进去后必须马上修改密码，不然下次登陆会报错。
mysql> show databases;
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
mysql> set global validate_password_policy=0; //只验证长度
注：如果这里设置有误使用mysql> INSTALL PLUGIN validate_password SONAME 'validate_password.so';
参考：https://www.cnblogs.com/alonely/p/10927541.html
mysql> set global validate_password_length=6; //修改密码长度,默认值是8个字符 注：感觉没用
mysql> alter user user()identified by"123456"; //修改登陆密码
查看密码验证策略
mysql> SHOW VARIABLES LIKE 'validate_password%';
上述操作的结果是——更改数据库用户root从本机访问时的密码，设为123456。
退出“mysql> ”环境，重新登录验证，必须采用新的密码才能登入：
[root@master51 mha-soft-student]# mysql -uroot -p"123456"
注：其他节点连接方式 >mysql -h 172.16.16.45 -P 3306 -uroot -p123
修改密码后：mysql>flush privileges;
五、设置所有机器都可以访问mysql服务
mysql> use mysql;
mysql> GRANT ALL ON *.* TO root@'%' IDENTIFIED BY '123456' WITH GRANT OPTION;
这句话的意思 ，允许任何IP地址（上面的 % 就是这个意思）的电脑 用admin帐户 和密码（admin）来访问这个MySQL Server
使配置生效
mysql>flush privileges;
查看版本
mysql> select version();
六、修改字符集
修改前
mysql> show variables like 'character_set_%';
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | latin1 |
| character_set_connection | latin1 |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | latin1 |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
vi /etc/my.cnf
[client]
default-character-set=utf8
[mysqld]
default-character-set=utf8
[mysql]
no-auto-rehash
default-character-set=utf8
重启数据库
修改后
mysql> show variables like 'character%';
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
创建数据库（一定要在修改字符集后在创建数据库，否则字符集不对）
mysql> create database example;
七、客户端问题：
问题：
使用Navicat Premium客户端执行语句成功后总出现如下报错
[Err] 1055 - Expression #1 of ORDER BY clause is not in GROUP BY clause and contains nonaggregated column 'information_schema.PROFILING.SEQ' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
解决方案：
select version(),@@sql_mode;
SET sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));
