I have the Ruby version ruby 1.9.2p0 (2010-08-18) [i386-mingw32] installed in Windows7. and the gem vesion 1.3.7
When i tried to install mysql gem, it is showing
Under Cygwin, I had to be sure to install not just libmysqlclient18, but also libmysqlclient-devel. Then "gem install mysql2" went fine.
There is also, of course, a ruby-mysql2 package in Cygwin.