pgloader will keep a separate file of rejected data, but continue trying to copy good data in your database.
pgloader also implements data reformatting, a typical example of that being the transformation of MySQL datestamps 0000-00-00 and 0000-00-00 00:00:00 to PostgreSQL NULL value
J. Leitner, and M. Haller. Proceedings of the 24th annual ACM symposium on User interface software and technology, page 593--602. New York, NY, USA, ACM, (2011)event-place: Santa Barbara, California, USA.