title: Delete from Oracle table rows older than 1 month
body: <p>In Oracle I have a table with a <code>DB_FLD_4</code> defined as <code>VARCHAR2(20 BYTE)</code> but actually holds DATE information with looks like this:</p>
  
  <pre><code>select DB_FLD_4 from DM_SUPDES_DISTRIB order by DB_FLD_4 desc;
  
  4/9/2017
  4/7/2017
  4/6/2017
  </code></pre>
  
  <p>Kind of m/d/yyyy format.</p>
  
  <p>I would like to create SP that would delete every day rows from the table older than 1 month.</p>
  
  <p>My sysdate looks like this:</p>
  
  <pre><code>select sysdate from dual;
  
  SYSDATE
  24-APR-17 04.41:00
  </code></pre>
  
  <p>Please help to manipulate formats to make this possible.</p>
  
  <p>Many thanks !!!</p>