这里似乎已经有几个问题。您尝试过他们的解决方案吗？
相关部分在这里：
At the time of building this gem, the necessary DLL files where availablein the following download:http://dev.mysql.com/get/Downloads/Connector-C/mysql-connector-c-noinstall-6.0.2-win32.zip/from/pickAnd put liblibmysql.dll file in your Ruby bin directory, for exampleC:Rubybin
