Doctrine select multiple objects - php

Question

I have 2 classes that I want to select from DB using 1 query in Symfony2 Doctrine.
The first entity is Calculation and the second is Polynomial. They have 1:1 relationship:
/**
* Acme\UserBundle\Entity\Calculation
*
* #ORM\Table(name="Calculation")
* #ORM\Entity(repositoryClass="AppBundle\Entity\CalculationRepository")
*/
class Calculation {
//...
/**
* #ORM\OneToOne(targetEntity="Polynomial")
* #ORM\JoinColumn(name="result_polynomial_id", referencedColumnName="id", nullable=false)
**/
private $resultPolynomial;
//...
}
I have a query, that returns me all Calculations of one user:
public function findByUser( $user ) {
return $this->getEntityManager()->createQuery(
'SELECT c
FROM AppBundle:User u
JOIN AppBundle:Polynomial p WITH u = p.user
JOIN AppBundle:Calculation c WITH p = c.resultPolynomial
WHERE u = :user
ORDER BY c.id'
)
->setParameter('user', $user)
->getResult();
}
And to the question... Is there a way to get resultPolynomials of the calculations in one query? If I use something like SELECT c, c.resultPolynomial I get error:
[Semantical Error] line 0, col 12 near 'resultPolynomial
': Error: Invalid PathExpression. Must be a StateFieldPathExpression.
And if I use foreach cycle all calculations to get the their resultPolynomials there are many queries to the DB (1 for each calculation) and it is not good for performance if I have many calculations.

Answer 1

I making a guess because you did not post your User definition nor your Polynomial definition.
I think you can make your DQL this way:
SELECT c, p
FROM AppBundle:User u
JOIN u.polynomial p
JOIN p.calculation c
WHERE u = :user
ORDER BY c.id
I guess you already defined your relations in your model so you don't need to repeat it here.