title: Ansi SQL type casting
body: <p>Is it allowed to cast types in ANSI SQL like in postgres for example:</p>
  
  <pre><code>SELECT SUM( CAST(qnty AS int) - CAST(reserve AS int) )  AS sum
  ...
  </code></pre>
  
  <p><em>qnty</em> and <em>reserve</em> are character columns.</p>