在执行命令 pip install mysql 或者 pip install mysqldb时候，报错
mysql_config: command not found
Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/v1/3z7bt9gs527g9x1r5r9ny1gw0000gn/T/pip-build-gAgOG7/MySQL-python/
原因是因为：
找不到mysql_config一般是由于通过lnmp.org或者其他方式安装mysql以后mysql_config是在/usr/local/mysql/bin/里面，这里面的文件不是在任意位置都可以访问的
解决方法：执行以下命令后重试即可
ln -s /usr/local/mysql/bin/mysql_config /usr/local/bin/mysql_config
将mysql_config链接到/usr/local/bin目录下
接着import MySql 又会报错，
Traceback (most recent call last):
File "/Users/fujunmin/files/python/selfPractise/youtube/flask/flaskFromScrach/app.py", line 10, in <module>
from flask_mysqldb import MySQL
File "/Users/fujunmin/anaconda/lib/python2.7/site-packages/flask_mysqldb/init.py", line 1, in <module>
import MySQLdb
File "/Users/fujunmin/anaconda/lib/python2.7/site-packages/MySQLdb/init.py", line 19, in <module>
import _mysql
ImportError: dlopen(/Users/fujunmin/anaconda/lib/python2.7/site-packages/_mysql.so, 2): Library not loaded: libmysqlclient.18.dylib
Referenced from: /Users/fujunmin/anaconda/lib/python2.7/site-packages/_mysql.so
Reason: image not found
sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/local/lib/libmysqlclient.18.dylib
含义是：在/usr/local/lib/libmysqlclient.18.dylib 创建一个/usr/local/mysql/lib/libmysqlclient.18.dylib的软连接
