<?php
 public function countAllOrderedByCreatedAt($firstResult)
    {
        $conn = $this->getEntityManager()->getConnection();

        $sql = 'SELECT count(*) FROM (SELECT * FROM post LIMIT 5 OFFSET :firstResult) as pg';

        $statement = $conn->prepare($sql);

        $statement->execute(['firstResult' => 20]);

        return $statement->fetch();
    }