title: ORA-01861: literal does not match format string in minus query
body: <p>I tried executing the following query:</p>
  
  <pre><code>select to_date(SUBJ_VST_FRM_VST_DT,'dd-MON-YY') 
  from SMARTTRIAL_ODR_LANDING.RAVE_LND_SUBJ_VST_FRM
  minus
  select SUBJ_VST_FRM_VST_DT 
  from SMARTTRIAL_ODR_STAGE.LS_STG_SUBJ_VST_FRM;
  </code></pre>
  
  <p>but the following error is returned: <code>ORA-01861: literal does not match format string</code></p>
  
  <p>What could the problem be?</p>