how can i add a two year filter to my reports in magento 1.9

Question

I want to add a two year interval filter to customer order by report grid ,but I have no idea about this.Anyone who have tried it please find me a way ,thanks in advance. I found to add code here in this path app\code\core\Mage\Reports\Model\Resource\Report\Collection.php
and code for a year interval is

$t['title'] =  $dateStart->toString('yyyy');
                        $t['start'] = ($firstInterval) ? $dateStart->toString('yyyy-MM-dd 00:00:00')
                            : $dateStart->toString('yyyy-01-01 00:00:00');

                        $lastInterval = ($dateStart->compareYear($dateEnd->getYear()) == 0);

                        $t['end'] = ($lastInterval) ? $dateStart->setMonth($dateEnd->getMonth())
                            ->setDay($dateEnd->getDay())->toString('yyyy-MM-dd 23:59:59')
                            : $dateStart->toString('yyyy-12-31 23:59:59');
                        $dateStart->addYear(1);

                        if ($dateStart->compareYear($dateEnd->getYear()) == 0) {
                            $dateStart->setMonth(1)->setDay(1);

                        $firstInterval = false;
                        break;
                        }

How can i modify this for two year interval period.

Answer 1

I got it done for me, here is the code

case '2year':
                        $t['title'] =  $dateStart->toString('yyyy').'-'.($dateStart->toString('yyyy')+1);
                        $t['start'] = ($firstInterval) ? $dateStart->toString('yyyy-MM-dd 00:00:00')
                            : $dateStart->toString('yyyy-01-01 00:00:00');

                        $lastInterval = ($dateStart->compareYear($dateEnd->getYear()) == 0);
                        Mage::log($lastInterval);
                        $t['end'] = ($lastInterval) ? $dateStart->setYear($dateEnd->getYear())->setMonth($dateEnd->getMonth())
                            ->setDay($dateEnd->getDay())->toString('yyyy-MM-dd 23:59:59')
                            : $dateStart->toString('yyyy-12-31 23:59:59');
                        $dateStart->addYear(2);

                        if ($dateStart->compareYear($dateEnd->getYear()) == 0) {
                            $dateStart->setMonth(1)->setDay(1);
                          }  
                        $firstInterval = false;
                        break;