title: Same id's but only fetch 1 result
body: <p>I'm about to make a message system. Instead of making 2 tables like <code>conversations</code> and <code>messages</code>, I would just like to have <code>messages</code>. There would then be a lot of rows with the same user id's like this:</p>
  
  <pre><code>id     to_id     from_id     message
  1      1         2           text...
  2      1         3           text...
  3      2         1           text...
  4      1         2           text...
  5      1         2           text...
  6      1         2           text...
  </code></pre>
  
  <p>The thing is, that I want to get one of each conversation. If id 1 writes to id 2, then thats 1 conversation, but if id 2 writes a reply to id 1, then it would STILL be only 1 conversation.</p>
  
  <p>In the above example, there is only 2 conversations (id 1 to id 3) and (id 1 to id 2 and reverse).</p>
  
  <p>How can i Achieve this. My idea is that there must be something simpler than DISTINCT.</p>