title: Oracle: handle different date format
body: <p>Assume we have a VARCHAR2 column called <code>MyDate</code>
  Assume it contains the following values:</p>
  
  <p>13/02/2001</p>
  
  <p>13-gen-2001</p>
  
  <p>I have to convert this field to a DATE value. But TO_DATE fails either on some values or on the others.</p>
  
  <pre><code>TO_DATE(MyDate, 'DD/MM/YYYY')
  </code></pre>
  
  <p>How can I convert it?</p>