Getting random results with Doctrine - php

Question

I'm new to Doctrine and had a hard time deciding how to get random rows within it without creating custom DQL functions or using a native query.
The solution I have come up with is below, this is within a custom repository for an Entity. I'm hoping for some constructive criticism in regards to it, however it currently is working.
class MyRepository extends EntityRepository
{
/**
* #param int $numberOfResults
* #return array
*/
public function getRandomResults($numberOfResults = 1)
{
$maxID = $this->getMax();
$count = 0;
$randomNumberCounter = 0;
$randomNumbers = array();
while ($randomNumberCounter < $numberOfResults) {
$randomNumberCounter++;
$randomNumbers[] = $this->getRandom(0, $maxID);
}
$qb = $this->createQueryBuilder('r');
while ($count < $numberOfResults) {
$qb
->andWhere(
$qb->expr()->orX(
// the greater than is to account for holes within the primary key
$qb->expr()->gte("r.id", "?".$count),
/* the less than is in case we have a beginning database with a large disparity
between starting and ending ID */
$qb->expr()->lte("r.id", "?".$count)
)
);
$count++;
}
$result = $qb
->setParameters($randomNumbers)
->setMaxResults($numberOfResults)
// ensure we have no duplicates
->groupBy('r.id')
->getQuery();
return $result->getResult();
}
/**
* get the maximum ID that the table has
* #return mixed
* TODO: Create a Cron job to set this every 6 hours
*/
public function getMax()
{
$maxID = $this->createQueryBuilder('r')
->select('(MAX(r.id))')
->getQuery()
->getSingleScalarResult();
return $maxID;
}
/**
* #param $min
* #param $max
* #return int
*/
public function getRandom($min, $max)
{
return mt_rand($min, $max);
}
}