Windows 7上安装gem mysql2

直接命令安装会失败

gem install mysql2

按照给出的提示

Please update your PATH to include build tools or download the DevKit
from 'http://rubyinstaller.org/downloads' and follow the instructions
at 'http://github.com/oneclick/rubyinstaller/wiki/Development-Kit'

继续安装，仍然失败，还需要mysql-connector（需要头文件和库文件）。
下载了mysql-connector-c-6.1.2-winx64

gem install mysql2 --platform=ruby -- '--with-mysql-lib="F:\mysql-connector-c-6.1.2-winx64\lib" --with-mysql-include="F:\mysql-connector-c-6.1.2-winx64\include"' 

安装成功