WHERE status='Review' OR
              ( ( status='Offered' OR
                   status='Denied' OR
                   status='Cancelled' OR
                   status='Conditional Offer') AND
                 ( sent_email is NULL OR
                   sent_email='0000-00-00')
             )

##</code><code>##

WHERE ( status='Offered' OR
                status='Denied' OR
                status='Cancelled' OR
                status='Conditional Offer') AND
              ( sent_email is NULL OR
                sent_email='0000-00-00');

##</code><code>##

my @proc_requests = $schema->resultset( 'TblRequests' )->search({
                -or => [
                      status => 'Offered',
                      status => 'Denied',
                      status => 'Cancelled',
                      status => 'Conditional Offer',
                          ],
                           -and => [
                               -or => [
                                    sent_email => {'!=', undef },
                                    sent_email => {'!=', '0000-00-00'},
                                ],
                            ],
                });