title: SQL to filter for records more than 30 days old
body: <p>Suppose I have the following query:</p>
  
  <pre><code>select customer_name, origination_date
  where origination_date &lt; '01-DEC-2013';
  </code></pre>
  
  <p>I would like to select all customers that have an origination date older than 30 days. Is there a way in SQL (oracle, if specifics needed) to specify it in a more dynamic approach than manually entering the date so that I don't need to update the query every time I run it?</p>
  
  <p>Thanks!</p>