symfony - Column Order by causes undefined index -

i have 3 entities, have relation each other:

entity 1:

/** @orm\onetomany(targetentity="articleorderreference", mappedby="purchaseorder") */ protected $purchaseorders; 

entity 2:

/** @orm\manytoone(targetentity="purchaseorder", inversedby="purchaseorders") */ protected $purchaseorder;   /** @orm\onetomany(targetentity="aosupplierreference", mappedby="articleorderreference")   *  @orm\orderby({"supplier" = "asc"})  * */ protected $articleorderreferences; 

entity 3:

/** @orm\manytoone(targetentity="articleorderreference", inversedby="articleorderreferences")  *    */ protected $articleorderreference;  /** @orm\manytoone(targetentity="supplier", inversedby="suppliers") */ protected $supplier; 

my goal create query this:

$order = $this->getdoctrine()->getmanager()->createquery("         select o, , s         acmeappbundle:purchaseorder o         join o.purchaseorders         join a.articleorderreferences s         o.id = :orderid           , s.supplier = :supplierid           , s.amount > 0              ")                    ->setparameter('orderid', $orderid)                    ->setparameter('supplierid', $supplierid)                    ->getoneornullresult(); 

but displays error

notice: undefined index: supplier in /var/www/symfony/vendor/doctrine/orm/lib/doctrine/orm/mapping/defaultquotestrategy.php line 40  

, since used @orm\orderby({"supplier" = "asc"}) in entity2. without order works. don't know why throws undefined index error. ideas how can fix this?

i know variable names badly chosen.