title: selecting minimum of multiple columns
body: <p>I have three decimal columns named list1,list2,list3.
  I want to find the minimum of three in a single query.<br>
  I've tired this:</p>
  
  <pre><code>SELECT Least(list1, list2, list3) 
  FROM   table1 
  </code></pre>
  
  <p>It throws an error that <code>least</code> is not recognized function.</p>