由于从所周知的原因，mysql不能在新版centos上用了。
其实很简单，网上很多文章的介绍其实都是来源于官网
它会自动为我们生成repo, 然后复制粘贴就行
创建repo文件，然后yum install MariaDB-server MariaDB-client就行
- 配置过程
1）先启动服务
systemctl start mariadb
是的，现在建议用systemctl替代service命令
2）再配置mysql_secure_installation
3）设置密码
这里不知道密码，中断了去设置密码
systemctl stop mariadb.service
mysqld_safe --user=mysql --skip-grant-tables --skip-networking &
然后输入sql指令
mysql 回车
MariaDB [mysql]> update mysql.user set authentication_string=password('123456') where user='root';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
MariaDB [mysql]> flush privileges;
Query OK, 0 rows affected (0.00 sec)
再回来mysql_secure_installation并输入密码，会有以下交互
Remove anonymous users? [Y/n] <– 是否删除匿名用户,生产环境建议删除，所以直接回车
… Success!
Normally, root should only be allowed to connect from 'localhost'. This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] <–是否禁止root远程登录,根据自己的需求选择Y/n并回车,建议禁止
… Success!
By default, MySQL comes with a database named 'test' that anyone can
access. This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] <– 是否删除test数据库,直接回车
以后这样登录：
mysql -uroot -p 并且输入密码，不能再只使用不安全的不带参数的mysql了
如果需要安装pdo_mysql记得只需要以下一句就可以了，不需要网上说的还要手动编译源码
yum install php-mysql
另外，需要远程访问的话：
GRANT ALL PRIVILEGES ON . TO 'root'@'%'IDENTIFIED BY '123456' WITH GRANT OPTION;
