How to select distinct query using symfony2 doctrine query builder? - php

Question

I have this symfony code where it retrieves all the categories related to a blog section on my project:
$category = $catrep->createQueryBuilder('cc')
->Where('cc.contenttype = :type')
->setParameter('type', 'blogarticle')
->getQuery();
$categories = $category->getResult();
This works, but the query includes duplicates:
Test Content
Business
Test Content
I want to use the DISTINCT command in my query. The only examples I have seen require me to write raw SQL. I want to avoid this as much as possible as I am trying to keep all of my code the same so they all use the QueryBuilder feature supplied by Symfony2/Doctrine.
I tried adding distinct() to my query like this:
$category = $catrep->createQueryBuilder('cc')
->Where('cc.contenttype = :type')
->setParameter('type', 'blogarticle')
->distinct('cc.categoryid')
->getQuery();
$categories = $category->getResult();
But it results in the following error:
Fatal error: Call to undefined method Doctrine\ORM\QueryBuilder::distinct()
How do I tell symfony to select distinct?

Answer 1

This works:
$category = $catrep->createQueryBuilder('cc')
->select('cc.categoryid')
->where('cc.contenttype = :type')
->setParameter('type', 'blogarticle')
->distinct()
->getQuery();
$categories = $category->getResult();
Edit for Symfony 3 & 4.
You should use ->groupBy('cc.categoryid') instead of ->distinct()

Answer 2

If you use the "select()" statement, you can do this:
$category = $catrep->createQueryBuilder('cc')
->select('DISTINCT cc.contenttype')
->Where('cc.contenttype = :type')
->setParameter('type', 'blogarticle')
->getQuery();
$categories = $category->getResult();

Answer 3

you could write
select DISTINCT f from t;
as
select f from t group by f;
thing is, I am just currently myself getting into Doctrine, so I cannot give you a real answer. but you could as shown above, simulate a distinct with group by and transform that into Doctrine. if you want add further filtering then use HAVING after group by.

Answer 4

Just open your repository file and add this new function, then call it inside your controller:
public function distinctCategories(){
return $this->createQueryBuilder('cc')
->where('cc.contenttype = :type')
->setParameter('type', 'blogarticle')
->groupBy('cc.blogarticle')
->getQuery()
->getResult()
;
}
Then within your controller:
public function index(YourRepository $repo)
{
$distinctCategories = $repo->distinctCategories();
return $this->render('your_twig_file.html.twig', [
'distinctCategories' => $distinctCategories
]);
}
Good luck!