title: CAST or Convert Within a SUM and Case
body: <p>Is it correct to implement a cast or convert in an aggregate SUM with a Case and if so, how would be the correct way to implement them? For example</p>
  
  <pre><code>    SUM(CASE WHEN X = 'Y' THEN Z ELSE 0.00 END)
  </code></pre>
  
  <p>In this case Z would be Cast or Converted, it is Datatype numeric, I'd like to convert it to varchar</p>