title: Oracle using REGEXP to validate a date field
body: <p>I am using Oracle 11G and I have a date column (Var char 2) where dates are manually entered into the database and unfortunately many times have invalid dates entered.  I would like to only select date field that are valid using some sort of REGEXP LIKE statement.  Here are the possible valid formats that I would like to select.</p>
  
  <pre><code>DATE
  
  JULY 31, 2009
  7/31/2009
  31-JUL-09
  </code></pre>
  
  <p>Anything that's not in these 3 possible formats I do not want to select.  Could someone please help me come up with a REGEXP or some other way to select these valid date formats.  Thanks in advance.</p>