title: Attempted to load class "Month" from namespace "DoctrineExtensions\Query\Mysql". Did you forget a "use" statement for another namespace
body: <p>I get the error <code>Attempted to load class "Month" from namespace "DoctrineExtensions\Query\Mysql". Did you forget a "use" statement for another namespace</code> when i'm trying to create a query that fetch data by year and month</p>
  
  <p>Inside my repository</p>
  
  <pre><code> public function getCongePris($mois,$annee,$matricule)
      {
          $emConfig = $this-&gt;_em-&gt;getConfiguration();
          $emConfig-&gt;addCustomDatetimeFunction('YEAR', 'DoctrineExtensions\Query\Mysql\Year');
          $emConfig-&gt;addCustomDatetimeFunction('MONTH', 'DoctrineExtensions\Query\Mysql\Month');
  
          $qb = $this-&gt;createQueryBuilder('co')-&gt;leftJoin('co.personnel','p');
          $qb-&gt;select('co')
              -&gt;where('p.matricule= :matricule')-&gt;andWhere('co.statutDemande=:statut ')
              -&gt;andWhere('MONTH( co.debutConge)=:mois')-&gt;andWhere('YEAR(co.debutConge)=:annee');
  
          $qb-&gt;setParameter('annee',$annee)-&gt;setParameter('mois',$mois)-&gt;setParameter('matricule',$matricule)-&gt;setParameter('statut','ACCEPTE');
  
          $conges = $qb-&gt;getQuery()-&gt;getResult();
          return $conges;
      }
  </code></pre>
  
  <p>Inside my config.yml</p>
  
  <pre><code>orm:
      auto_generate_proxy_classes: "%kernel.debug%"
      naming_strategy: doctrine.orm.naming_strategy.underscore
      auto_mapping: true
          dql:
              string_functions:
                  MONTH: DoctrineExtensions\Query\Mysql\Month
                  YEAR: DoctrineExtensions\Query\Mysql\Year
  </code></pre>