On Jun 9, 8:38  㮮 
> [Note:         
>
> Hello guys,
>
> I am new to Ruby. I have been working with the core language so far
> without problems. Now I am starting to use mysql.
>
> I have installed it with gem install mysql, and it work perfectly. If I
> run gem list, I get the following:
>
> sh-3.2# gem list
>
> *** LOCAL GEMS ***
>
> actionmailer (2.1.0, 1.3.6)
> actionpack (2.1.0, 1.13.6)
> actionwebservice (1.2.6)
> activerecord (2.1.0, 1.15.6)
> activeresource (2.1.0)
> activesupport (2.1.0, 1.4.4)
> acts_as_ferret (0.4.3, 0.4.1)
> capistrano (2.3.0, 2.0.0)
> cgi_multipart_eof_fix (2.5.0, 2.2)
> daemons (1.0.10, 1.0.9, 1.0.7)
> dnssd (0.6.0)
> fastthread (1.0.1, 1.0)
> fcgi (0.8.7)
> ferret (0.11.6, 0.11.4)
> gem_plugin (0.2.3, 0.2.2)
> highline (1.4.0, 1.2.9)
> hpricot (0.6)
> libxml-ruby (0.5.4, 0.3.8.4)
> mongrel (1.1.5, 1.1.4, 1.0.1)
> mysql (2.7)
> needle (1.3.0)
> net-scp (1.0.1)
> net-sftp (2.0.1, 1.1.0)
> net-ssh (2.0.2, 1.1.2)
> net-ssh-gateway (1.0.0)
> rails (2.1.0, 1.2.6)
> rake (0.8.1, 0.7.3)
> RedCloth (3.0.4)
> ruby-openid (2.0.4, 1.1.4)
> ruby-yadis (0.3.4)
> rubygems-update (1.1.1)
> rubynode (0.1.5, 0.1.3)
> sqlite3-ruby (1.2.2, 1.2.1)
> termios (0.9.4)
>
> As you can see mysql 2.7 is installed. When I put the line require "mysql"n the first line of my program, I get the following error:
>
> sh-3.2# ruby learn.rb
> learn.rb:1:in `require': no such file to load -- mysql (LoadError)
> from learn.rb:1
>
> I am on Mac OS X 10.5.3 with Ruby 1.8.6, and the outputs included in the
> email have been generated with "root". Any ideas why it is not working?
>

try this:

require 'rubygems'
require 'mysql'

mysql being installed as gem require you first load rubygems to work
(unless you have RUBYOPT=rubygems which is not your case).

HTH,
--
Luis Lavena