Symfony2 Doctrine query implode invalid arguments passed - php

Question

I have tried searching around and even the example in the Symfony2 documentation, and have been struggling with writing a query to select all blog posts by post category and to order them in descending order by Id.
However I have the following error when i run the code. Any suggestions?
ContextErrorException in SimpleArrayType.php line 51:
Warning: implode(): Invalid arguments passed
I am creating a blog, for learning purposes and am trying to retrieve posts from my posted table with the following columns.
Id |postTitle | postDescription | postContent | postCategory
My Entity looks like this, (showing most relevant sections)
/**
* posted
*
#ORM\Table()
* #ORM\Entity
*/
class posted
{
/**
* #ORM\Column(type="string", length=500)
*/
protected $postTitle;
/**
* #ORM\Column(type="string", length=500)
*/
protected $postDescription;
/**
* #ORM\Column(type="string", length=500)
*/
protected $postContent;
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
protected $id;
/**
* #ORM\Column(type="datetime", name="posted_at")
*/
protected $datePosted;
/**
*#var array
* #ORM\Column(type="simple_array", length=250)
*/
protected $postCategory;
/**
* Get id
*
* #return integer
*/
public function getId()
{
return $this->id;
}
/**
* Set postCategory
*
* #param string $postCategory
* #return posted
*/
public function setPostCategory($postCategory)
{
$this->postCategory = $postCategory;
return $this;
}
/**
* Get postCategory
*
* #return string
*/
public function getPostCategory()
{
return $this->postCategory;
}
My Controller looks like
/**
* this is the EPL page of posts of EPL category
*
* #Route("/EPL", name="eplposts")
* #Method("GET")
* #Template()
*/
public function eplAction()
{
$em = $this->getDoctrine()->getManager();
$entities = $em->getRepository('BlogBundle:posted')->findBy(array('postCategory' => 'English Premier League','id' => 'desc'));
return $this->render('BlogBundle:Default:EPLpost.html.twig',array(
'entities' => $entities,
));
}

Answer 1

I suggest that you create your own query method in the repository of your entity, for example, something like this :
class BoardRepository extends EntityRepository
{
public function findByCategory($category)
{
$builder = $this->createQueryBuilder('p');
$builder
->where($builder->expr()->like('p.postCategory', '%'.$category.','))
->orWhere($builder->expr()->like('p.postCategory', ','.$category.'%'))
;
return $builder->getQuery()->execute();
}
}