doctrine querybuilder $qb -> expr()-> all - symfony

Question

I'm working with Symfony2. I have to list last $nbOpe entities of Entity OpeEntetes. The following script gives me error:
Blockquote
[Doctrine\ORM\Query\QueryException]
[Semantical Error] line 0, col 16 near 'ALL(SELECT FROM': Error: Class 'ALL' is not defined.
Blockquote
What to do ?
public function essai1($nbOpe){
$in = $this->_em->createQueryBuilder()
->from('GcRequetesBundle:OpeEntetes','ein')
->orderBy('ein.oeNumOpe', 'DESC')
->setMaxResults($nbOpe);
$qb = $this->_em->createQueryBuilder();
$qb
-> add("select",new Expr\Select(array('res')))
-> add('from', new Expr\From($qb -> expr()-> all($in -> getDql()), 'res'));
$query = $qb -> getQuery();
$result= $query -> getArrayResult();
return $result;
}

Answer 1

There are couple of errors in your code:
subqueries do no support setMaxResults Enabling LIMIT resp. setMaxResults on subquery
from field does not support subqueries Subquery into FROM
you have probably misunderstood what the ALL expression means and for what it is used for For example MySql documentation about ALL
In any case, the restriction that subqueries do not support the setMaxLimits probably means that you cannot build your code in this way at all. If that isn't a show-stopper for you, then you could try it with the following code for example (easiest would be to just have one query, but I assume you have some reason for doing this in two steps...):
$in = $em->createQueryBuilder()
->select('ein')
->from('GcRequetesBundle:OpeEntetes','ein')
->orderBy('ein.oeNumOpe', 'DESC')
->setMaxResults($nbOpe); // this does not affect the result at all
$qb = $em->createQueryBuilder();
$qb->add('select', 'ein2');
$qb->add('from', 'GcRequetesBundle:OpeEntetes ein2');
$qb->add('where', $qb->expr()->eq('ein2.id', $qb->expr()->any($in->getDql())));
$query = $qb -> getQuery();
$result= $query -> getArrayResult();
return $result;