title: Fetch unique combinations of two field values
body: <p>Probably it has been asked before but I cannot find an answer.</p>
  
  <p>Table Data has two columns:</p>
  
  <pre><code>Source   Dest
  1         2
  1         2
  2         1
  3         1
  </code></pre>
  
  <p>I trying to come up with a MS Access 2003 SQL query that will return:</p>
  
  <pre><code>1       2
  3       1
  </code></pre>
  
  <p>But all to no avail. Please help! </p>
  
  <p>UPDATE: exactly, I'm trying to exclude 2,1 because 1,2 already included. I need only unique combinations where sequence doesn't matter.</p>