title: How do I check for blank in DataView.RowFilter
body: <p>Assuming I have a column called A and I want to check if A is null or blank, what is the proper way to check for this using the DataView's RowFilter:</p>
  
  <pre><code>DataTable dt = GetData();
  
  DataView dv = new DataView(dt);
  
  dv.RowFilter = "A IS NOT NULL OR A IS NOT ''";
  </code></pre>
  
  <p>The above doesn't seem to work though.</p>