title: How to sort results from UNION
body: <p>I have a query like this:</p>
  
  <pre><code>(select @number:=3) 
    union 
  (select @number:=2) 
    union 
  (select @number:=1) 
  order by @number ASC
  </code></pre>
  
  <p>With results:</p>
  
  <pre><code>3
  2
  1
  </code></pre>
  
  <p>But I would like the results in ascending order, like this:</p>
  
  <pre><code>1
  2
  3
  </code></pre>
  
  <p>How can I achieve the results in ascending order with a query like this?</p>