title: How to use "mysql2" gem in Rails 3 application on Windows 7?
body: <p>I try to install the <code>mysql2</code> gem on Windows 7 32-bit.</p>
  
  <p>I run:</p>
  
  <pre><code>gem install mysql2
  </code></pre>
  
  <p>and I get the following error:</p>
  
  <pre><code>ERROR:  Error installing mysql2:
          The 'mysql2' native gem requires installed build tools.
  
  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'
  </code></pre>
  
  <p>Any ideas what could cause this error, and how to solve this ?</p>
  
  <hr>
  
  <p><strong>UPDATE</strong></p>
  
  <p>I did everything as described <a href="http://rorguide.blogspot.com/2011/03/installing-mysql2-gem-on-ruby-192-and.html">here</a>, but I can't figure out the last step:</p>
  
  <pre><code>gem install mysql2 -- 
       '--with-mysql-lib="c:\Program Files\MySQL\MySQL Server 5.1\lib\opt" 
        --with-mysql-include="c:\Program Files\MySQL\MySQL Server 5.1\include"'
  </code></pre>
  
  <p>I understand that I should change the paths to the correct paths in my system, but I can't find the <code>lib\opt</code> and the <code>include</code> directories in my WAMP MySQL installation. I use WAMP 2.1.</p>
  
  <p>Please advise.</p>