title: How to find unique rows from a Ruby variable containing database rows
body: <p>I have these line of code in Ruby:</p>
  
  <pre><code>connection = ActiveRecord::Base.connection()
  @mastertest = connection.execute("select code_ver, suite, date from mastertest order by date desc limit 30")
  </code></pre>
  
  <p>So mastertest contains all the rows from my database table.</p>
  
  <p>I want only all rows which have a unique value of code_ver from the results. How do I find that ?</p>