This new site is migrated from Joomla to Drupal. Most users were created 44 years ago and they should not be. I found out the created date format is different between Joomla and Drupal. So, how can I migrate or convert Joomla created date(something like this "2008-08-05 20:20:42.000000") to Drupal(something like "1335285830")?
Additional information
PS: I output Joomla Created Date as CSV.
