title: Cannot see "Null" value in Redshift table column
body: <p>I have a table in redshift with following columns in create statement</p>
  
  <pre><code>ExpiryDate Timestamp without time zone          NULL Encode zstd,
  IssueDate Timestamp without time zone           NULL Encode zstd,
  RewardNumber varchar(64)                        NULL Encode zstd,
  VoucherIdentifier varchar(64)                   NULL Encode zstd
  </code></pre>
  
  <p>Once I insert data into my table I can see NULL value for "ExpiryDate" and "IssueDate" but I have no clue why I am not able to see any NULL value for "RewardNumber" and "VoucherIdentifier". It simply shows blank for the two columns. I am using DBvisualizer to connect to redshift. </p>
  
  <p><img src="https://i.stack.imgur.com/qvqIb.png" alt="See Screenshot of my DBVisualizer"></p>
  
  <p>Am I doing something wrong when I am creating my tables</p>