title: How does UNION ALL return blanks in one column and data in another?
body: <p>I've a View that has two SELECT statements returning data using UNION ALL. </p>
  
  <pre><code>SELECT column1, column2, column3, column4
  FROM table1
  UNION ALL
  SELECT column1, column2, column3, column4
  FROM table2
  </code></pre>
  
  <p>So, all the columns in table1 are supposed to display data because column4='A'. However, in table2, column2 should return blanks/null because column4='B'. Keep in mind, column2 in table2 DOES contain data, but in the View, we only want to return blank/nulls.</p>