rpm -qa | grep mysql
#可能的显示情况如下
#mysql-community-libs-8.0.12-1.el7.x86_64
#mysql80-community-release-el7-1.noarch
#mysql-community-client-8.0.12-1.el7.x86_64
#mysql-community-common-8.0.12-1.el7.x86_64
#mysql-community-server-8.0.12-1.el7.x86_64
#通过下面的命令进行删除
yum remove mysql-xxx-xxx-


#查找mysql的相关文件
find / -name mysql

#根据自身的需求删除mysql的配置文件信息
rm -rf /var/lib/mysql

rpm -qa | grep mariadb
#查找mariadb
#可能出现的结果mariadb-libs-5.5.56-2.el7.x86_64
#将查找出来的结果进行强制删除
rpm -e --nodeps mariadb-libs-5.5.56-2.el7.x86_64

cd /usr/src
wget https://dev.mysql.com/get/mysql80-community-release-el7-1.noarch.rpm

#安装yum源
yum localinstall mysql80-community-release-el7-1.noarch.rpm

#更新yum源
yum clean all
yum makecache

#开始安装MySQL
yum install mysql-community-server

#启动MySQL
systemctl start mysqld

#启动成功后可以查看初始化密码随机生成的
cat /var/log/mysqld.log | grep password

#登录MySQL修改mysql用户密码
mysql -u root -p
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'yourpassword';
#远程设置
mysql> use mysql;
mysql> update user set host='%' where user='root';
#授权用户名的权限，赋予任何主机访问数据的权限
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;

#允许myuser用户使用mypassword密码从任何主机连接到mysql服务器
GRANT ALL PRIVILEGES ON *.* TO 'myuser'@'%'IDENTIFIED BY 'mypassword' WITH GRANT OPTION;
#允许用户myuser从ip为192.168.1.6的主机连接到mysql服务器，并使用mypassword作为密码
GRANT ALL PRIVILEGES ON *.* TO 'myuser'@'192.168.1.3'IDENTIFIED BY 'mypassword' WITH GRANT OPTION;

#启动mysql
systemctl start mysqld.service

#结束
systemctl stop mysqld.service

#重启
systemctl restart mysqld.service

#开机自启
systemctl enable mysqld.service

#修改加密规则 （这行我没有写，不过貌似也可以）密码需要设置包含大小写字母符号和数字的格式，否则设置不会超成功
ALTER USER 'root'@'%' IDENTIFIED BY 'password' PASSWORD EXPIRE NEVER; 
#更新一下用户的密码 
ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY 'password'; 
#刷新权限
FLUSH PRIVILEGES;