windows下多个python版本共存
1、安装不同版本的python
www.python.org/downloads/,准备装个2.6.6，装个3.4.1
https://www.python.org/download/releases/2.6.6/
https://www.python.org/downloads/release/python-341/
https://www.python.org/ftp/python/2.6.6/python-2.6.6.amd64.msi
https://www.python.org/ftp/python/3.4.1/python-3.4.1.amd64.msi
https://www.python.org/ftp/python/3.4.1/python-3.4.1.amd64-pdb.zip
2、设置环境变量，包括python、python/Scripts目录，想用哪个版本，就把哪个版本的环境变量写在前面
3、安装mysql包
百度"python mysql"，进入下载页面：http://dev.mysql.com/downloads/connector/python/，选择版本