title: Oracle: CaseState with ISNULL condition
body: <p>I have the below case statement that is not capturing is null values. How can I add another criteria to capture when REGION_NAME is null </p>
  
  <pre><code>CASE WHEN M.OPER_STATE = 'AK' AND REGION_NAME IN ('NA','N/A','')
    THEN 'Pacific'
    ELSE T.REGION
  END REGION
  </code></pre>
  
  <p>The folling row returns blank for region and should return Pacific.</p>
  
  <pre><code>Region    Id    REGION_NAME
            1      (THIS VALUE IS NULL)
  </code></pre>