第一章 检查是否安装了Mysql
1.1 yum检查
yum list installed | grep mysql
1.2 安装则直接删除
yum remove xxx
1.3 rpm检查
rpm -qa | grep -i mysql
有则直接删除
rpm -e --nodeps xxx
第二章 正式安装MySQL
2.1 yum安装，下载mysql
wget --no-check-certificate http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm
2.2 开始安装
yum -y install mysql-community-server --nogpgcheck
2.3 启动
//启动
systemctl start mysqld.service
//查看状态
systemctl status mysqld.service
2.4 获取初始密码
grep "password is" /var/log/mysqld.log
使用密码登陆数据库，首次登陆，需要重新设置新密码
mysql -uroot -p
登录进去后 更改密码弱口令设置，设置简单密码
|-----------------------------------------------------------------------------------------------|
| mysql> set global validate_password_policy=0; mysql> set global validate_password_length=1; |
设置新的密码：
|---------------------------------------------------------------------------------------|
| mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'root'; mysql> flush privileges; |
配置远程登录：
|---------------------------------------------------------------------------------------------------|
| mysql> grant all privileges on *.* to root@'%' identified by 'root'; mysql> flush privileges; |
重启mysql
|--------------------------|
| systemctl restart mysqld |