Laravel Mongo Many To Many relation wherehas not working

Question

I have two mongo documents that are related to each other in a many to many relationship. One is called Lawyer and the other LawCase.

My Lawyer model has:

public function cases()
    {
        return $this->belongsToMany('App\LawCase');
    }

My LawCase model has:

public function lawyers()
    {
        return $this->belongsToMany('App\Lawyer');
    }

All I am trying to do is find lawyers that have a certain category of law cases.

$lawyers = App\Lawyer::whereHas('cases', function($q){
                            $q->where('category', '=', 'DUI');
                            })->get();

This gets nothing even though I have lawcase documents that have a category of 'DUI'.

When I do

$lawyers = App\Lawyer::with('cases')->get();

That gets me a result set. Just having some issues with wherehas. What am I missing?

I tried researching the issue but looks like others may have similar issue:

Laravel + Jenssegers\Mongodb: 'WhereHas' and 'Has' returns empty collection

If whereHas would not work, how would you get about doing this?

UPDATE:

My Lawyer Document

{ 
    "_id" : ObjectId("5945f88c9a89205aae0efea8"), 
    "full_name" : "Some Name ", 
    "active" : true, 
    "updated_at" : ISODate("2017-06-18T03:50:36.849+0000"), 
    "created_at" : ISODate("2017-06-18T03:50:36.849+0000"), 
    "law_case_ids" : [
        "5945f88c9a89205aae0efea9", 
        "5945f88c9a89205aae0efeac", 
        "5945f8b59a89205aae0f3f81", 
        "5955d0ff9a89200a57340db8"
    ]
}

My LawCase Document

{ 
    "_id" : ObjectId("5945f88c9a89205aae0efe9a"), 
    "category" : "DUI", 
    "updated_at" : ISODate("2017-06-18T03:50:36.825+0000"), 
    "created_at" : ISODate("2017-06-18T03:50:36.821+0000"), 
    "lawyer_ids" : [
        "5945f88c9a89205aae0efe99"
    ]
}

Answer 1

Here is the correct way to do it, this will return the lawyers who have cases that match the category DUI.

$lawyers = App\Lawyer::with(['cases'=> function($q){
                            $q->where('category', '=', 'DUI');
                            }])->get();