title: Select distinct and non-distinct column values
body: <p>I want to run a query that eliminates duplicate rows based on the values of colA and colB.
  However, I still want to return the values of colC and colD.</p>
  
  <p>Here is a simple example of what I have so far:</p>
  
  <pre><code>SELECT DISTINCT colA, colB   ?colC, colD?
  FROM TABLE1
  </code></pre>
  
  <p>or</p>
  
  <pre><code>SELECT colA, colB    ?colC, colD?
  FROM TABLE1
  GROUP BY colA, colB
  </code></pre>
  
  <p>Either method does not allow me to return colC, and colD unless I check them as distinct values or group like colA and colB.  I do not want to do this, only colA and colB together need to be distinct not colC and colD.  I just want to return them.</p>
  
  <p>Any ideas on how I can accomplish this?</p>