title: convert case statement to where condition
body: <p>I am trying to convert this case statement:</p>
  
  <pre><code>(CASE UPPER(dc.source_name) WHEN 'DART' THEN dc.ad_campaign_id ELSE dc.cfid END) AS rodeo_order_id
  </code></pre>
  
  <p>into a condition in the <code>where</code> clause.</p>
  
  <p>Any help is appreciated!</p>
  
  <p>Thanks,
  S</p>