mysqld --initialize --console
设置权限：
chown -R mysql:mysql /var/lib/mysql
启动服务：
systemctl start mysqld
查看临时密码：
cat /var/log/mysqld.log |grep localhost
更改Mysql登录密码：
alter user 'root'@'localhost' identified by '123456';
查询在哪：
whereis mysql
安装步骤：
rpm -ivh mysql-community-common-8.0.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-plugins-8.0.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-8.0.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-8.0.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-icu-data-files-8.0.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-8.0.28-1.el7.x86_64.rpm
检查是否 有：
rpm -qa|grep mariadb
有：rpm -e --nodeps mariadb-libs
