title: Case statement to determine if I should union
body: <p>I currently want to do some sort of conditional union. Given the following example:</p>
  
  <pre><code>SELECT  age, name
  FROM    users
  UNION
  SELECT  25 AS age, 'Betty' AS name
  </code></pre>
  
  <p>Say I wanted to only union the second statement if the count of 'users' was >=2 , otherwise do not union the two.</p>
  
  <p>In summary I want to append a table with a row if the table only has 2 or more values.</p>