由于小伙伴，事先手动安装了mysql，导致了一部分问题
彻底删除mysql
yum remove mysql mysql-server mysql-libs;find / -name mysql 将找到的相关东西delete掉；rpm -qa|grep mysql(查询出来的东东yum remove掉)yum remove mariadb
安装
yum -y install mariadb-server
systemctl mariadb操作
//启动systemctl start mariadb.service//开机启动systemctl enable mariadb//状态systemctl status mariadb//停止systemctl stop mariadb