title: SQL Query DIFFDATE Returns Invalid Identifier
body: <p>I am trying to display the difference in days between 2 columns using diffdate, using the following code:</p>
  
  <pre><code>SELECT
    ORDERS.ORDERID,
    ORDERS.CUSTOMERID,
    ORDERS.ORDERDATE,
    ORDERS.SHIPDATE,
    DATEDIFF ( DAY, ORDERS.ORDERDATE, ORDERS.SHIPDATE)
  FROM
    ORDERS
  </code></pre>
  
  <p>But it comes out with Invalid Identifier - Where am I going wrong?</p>
  
  <p>Thanks for any help!</p>