How to select randomly with doctrine

Question

Here is how I query my database for some words

$query = $qb->select(\'w\')
    ->from(\'DbEntities\\Entity\\Word\', \'w\')
    ->where(\'w.indiction         


        

Answer 1

@Krzysztof's solution is IMHO best here, but RAND() is very slow on large queries, so i updated @Krysztof's solution to gives less "random" results, but they are still random enough. Inspired by this answer https://stackoverflow.com/a/4329492/839434.

namespace Project\ProductsBundle\Entity;

use Doctrine\ORM;

class ProductRepository extends ORM\EntityRepository
{
    /**
     * @param int $amount
     * @return Product[]
     */
    public function getRandomProducts($amount = 7)
    {
        return $this->getRandomProductsNativeQuery($amount)->getResult();
    }

    /**
     * @param int $amount
     * @return ORM\NativeQuery
     */
    public function getRandomProductsNativeQuery($amount = 7)
    {
        # set entity name
        $table = $this->getClassMetadata()
            ->getTableName();

        # create rsm object
        $rsm = new ORM\Query\ResultSetMapping();
        $rsm->addEntityResult($this->getEntityName(), 'p');
        $rsm->addFieldResult('p', 'id', 'id');

        # sql query
        $sql = "
            SELECT * FROM {$table}
            WHERE id >= FLOOR(1 + RAND()*(
                SELECT MAX(id) FROM {$table})
            ) 
            LIMIT ?
        ";

        # make query
        return $this->getEntityManager()
            ->createNativeQuery($sql, $rsm)
            ->setParameter(1, $amount);
    }
}