Laravel MongoDB combining raw select count and group by

Question

I am using jenssegers/laravel-mongodb

I was wondering if I can do this with mongodb aggregate. I have a dataset of

And I am trying to achieve this kind of result or anything close that I can loop into

What I have right now is this:

$collegeGender = FormData::raw( function ( $collection ) {
        return $collection->aggregate([
                ['$sortByCount' => [
                    '$mergeObjects' =>[
                        '$details.college',
                        '$details.gender'
                    ]
                ]]
            ]);
    });

But it is displaying an error:

$mergeObjects requires object inputs, but input "M" is of type string

Here is a sample of my collection data

{
   '_id': '5d5d77de54f57118ac003b46',
   'details': {
      'age' : 'M',
      'college' : 'College 1',
   }
}

I also don't know if I am using the aggregate function correctly :)

Answer 1

'age' and 'college' are not objects, they're just string fields, so you can't merge them using $mergeObjects instead you should use $concat