已解决;

1. 确保安装xcode;

2. brew 检测 brew doctor; 显示Your system is ready to brew.

3. brew升级, brew update;升级过程很慢, 也有些许问题, github 上brew关于更新问题,

cd "$(brew --repo)" && git fetch && git reset --hard origin/master && brew update

github中指出可以在遇到问题时对brew doctor和brew update多执行两次,

4.删除原来的Mariadb, brew uninstall mariadb; 重新安装brew install mariadb;
5.启动mysql.server start;
6.链接mysql -uroot,

Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 4
Server version: 10.1.19-MariaDB Homebrew

Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> 

Every thing is OK