title: Removing entries with duplicates in specific columns SQL
body: <p>I have 3 columns: A B C. I only want rows that share the same value in col A but different values for both B and C. </p>
  
  <pre><code>1 | item1 | Jan | Amy
  2 | item1 | Feb | Amy
  3 | item2 | Mar | Bob
  4 | item2 | Mar | Bill
  5 | item3 | Apr | Charles
  6 | item3 | May | Doug
  7 | item4 | Jun | Felix
  </code></pre>
  
  <p>Out of the example above. I want it to show rows 5, 6 and 7.</p>
  
  <p>Is there any good way of doing this?</p>