empty string inserted as null

[lianji-li]

My solution is check quoted when $field eq ''

		if ($field eq '') # fast exit for empty (should mean null)
		{
			if ($colnull[$num] == 1)
			{
                                    my $quoted = $csv->is_qoted($num);   # keep empty string
				$field = $quoted ? '' : '\N';
			}
			# No need to set it at '' if null isn't authorized, it is already
			$outrow.= $field;
			next;
		}