How can i select extra fields and map them to entity via doctrine query builder in symfony?

Question

I have two entities: Category and Product. Category entity has not link to Product (protected $products // ArrayColection) . I need to calculate total amount of product prices inside each category, and i need to do it ONLY IN SINGLE request via query builder.

Can i do something like this:

$categories = $categoryRepository->createQueryBuilder('c')->join('AppBundle:Product', 'p')->addSelect('SUM(p.price) as c.totalPrice')->addGroupBy('c.id')->getQuery()->getResults();

And then map attribute totalPrice to entity, to have access to it somehow like this:

$categories->get(0)->totalAmount

I CAN'T build extra query, and i CAN'T add relationsip field to Category ($products) to calculte totalSum in entity method by adding price of each product. I should done it only with single query...

Answer 1

What you are talking about is possible with Doctrine > 2.4

Check out their docs for more details on joins: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/dql-doctrine-query-language.html

Meanwhile - this is what should work for you:

$query = $this->createQueryBuilder('c')
            ->leftJoin('AppBundle:Product', 'p', 'WITH', 'p.category = c.id')
            ->select('SUM(p.price) as totalPrice')
            ->groupBy('c.id');

Note how we use the leftJoin method parameters - this is what allows you to run the query despite there is no relation between tables.

Hope that works for you