I've got this data in my DB:
I try to get the foreign_ids with the latest created_at value of a guest_identifier.
In this case I would expect:
    foreign_id: 5 for guest_identifier: 12345
    foreign_id: 5 for guest_identifier: 2345
    foreign_id: 4 for guest_identifier: 345
Now I want to count this results and return something like:
[
   {
       "foreign_id": 5,
       "occurrence": 2
   },
   {
       "foreign_id": 4,
       "occurrence": 1
   }
]
This is how I try to get this result:
$qb = $this->createQueryBuilder('statistic')
        ->select('statistic.foreignId, COUNT(statistic.foreignId) as occurrence')
        ->where('statistic.guideId = :guideId')
        ->andWhere('statistic.type = :type')
        ->andWhere('statistic.createdAt BETWEEN :startDate AND :endDate')
        ->groupBy('statistic.guestIdentifier')
        ->setParameters(array(
            'guideId' => $guideId,
            'type' => 'answer_clicked',
            'startDate' => $startDate,
            'endDate' => $endDate
        ))
        ->getQuery();
    $stats = $qb->getResult();
    return $stats;
The problem is, that my result looks like this:
[
  {
    "foreignId": 5,
    "occurrence": "3"
  },
  {
    "foreignId": 5,
    "occurrence": "3"
  },
  {
    "foreignId": 4,
    "occurrence": "2"
  }
]
I can't find, why the occurrence is 3 instead of 2 for foreign_id: 5 and why occurrence is 2 instead of 1 for foreign_id: 3. Also I don' know how to group the results another time.

 
    