title: Get first value as NULL in SELECT query result
body: <p>I have a query:</p>
  
  <pre><code>Select Col1 from tbl1 where Col2= 'abc'; 
  </code></pre>
  
  <p>The result will be:</p>
  
  <pre><code>Col1
  -----
  David  
  Harman  
  Joe 
  </code></pre>
  
  <p>I want to add NULL in my result set and I don't have any entry in my Col1 which is NULL. So result should be:</p>
  
  <pre><code>Col1  
  -----
  NULL  
  David  
  Harman  
  Joe  
  </code></pre>