https://blog.****.net/smiles13/article/details/81460617 （部分参考）
先查看是否安装mariadb
rpm -qa | grep mariadb
卸载 rpm -e --nodeps mariadb-libs-5.5.60-1.el7_5.x86_64
报错处理：
初始化错误：
（1） [ERROR] --initialize specified but the data directory has files in it. Aborting. https://www.jianshu.com/p/96ba3424e23c
根据my.cnf 清空目录 rm -rf /var/lib/mysql
（2） [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
https://blog.****.net/jacke121/article/details/79884678 打开/etc/my.cnf修改
#开启查询缓存 explicit_defaults_for_timestamp=true