title: How to get page number from item name in Oracle?
body: <p>I am working with Oracle Apex.
  I'm trying to get page number from an item name like <code>P11_USER_NAME</code>
  but, if I use <code>substr</code> function, then it's returning an error <em>invalid number</em>.</p>
  <p>I hope to find any easy solution.</p>