error "Call to a member function count() on null" when using laravel orm

Question

I want to do the following query with the ORM of Laravel:

public function rate_already_existing(Request $request)
    {
        $requests = DB::table('requests')
            ->join('feedbacks', 'requests.id', '=', 'feedbacks.request_id')
            ->select('requests.id')
            ->where('requests.id', '=', $request->input('assistanceRequestId'))
            ->get();

        if(count($requests) > 0) {
            return true;
        }
    }

The function should check if a request have already a feedback... in that case it returns true. The function above works, but I would like to do that function with the ORM to avoid too many rows and I tried the following:

public function rate_already_existing(Request $request)
{
    $request_match = Req::find($request->input('assistanceRequestId'))->feedback->count();

    if($request_match > 0) {
        return true;
    }
}

Unfortunately using the second function when the query have no rows the following error appears:

Call to a member function count() on null

Request model and feedback model have a one-to-one relationship.

Can help?

Anuj Shrestha · Accepted Answer · 2020-05-14 05:37:02Z

The error occurs when

Req::find($request->input('assistanceRequestId'))

is not able to find the row on the table. So it returns null. or when your relationship data return null use if condition to determine if data exists then try to use count method.

And since you are trying to get the count of the relationship directly why not use

 $request_match = Req::where('id', $request->input('assistanceRequestId'))->withCount('feedback')->first();

This withCount gives you the count of the relationship as 'feedback_count.

so you can use it like,

  if($request_match && $request_match->feedback_count > 0){
     return true
  }

But if you wanna only check if feedback exists and don't care about the data fetched since you are returning boolean data then try this,

$hasFeedback = Req::where('column_name', $request->input('assistanceRequestId'))->has('feedback')->exists();

return $hasFeedback;

This takes less resource and is faster than loading full data from the database and performing count check. To learn more about has() method and its importance for a scenario like yours try to check out the larval doc's Querying Relationship Existence

Digvijay · Accepted Answer · 2020-05-13 10:09:30Z

0

You can take leverage of withCount().

$request_match = Req::find($request->input('assistanceRequestId'))->withCount('feedback')->get();

if($request_match->feedback_count > 0) {
    return true;
}

answered May 13, 2020 at 10:09

Digvijay

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3 Comments

Anuj Shrestha Over a year ago

but this will still gives you Call to a member function withCount() on null error if find methods returns null. Since you are first trying to load the data and then trying to get the relationship count of the returned eloquent Model object.

Michele Della Mea Over a year ago

It appears the following error: Property [feedback_count] does not exist on the Eloquent builder instance.

Digvijay Over a year ago

Or you can simply do ->has('feedback')->get() and your condition would be if($request_match)

Kent · Accepted Answer · 2020-05-13 10:21:00Z

0

Try this

public function rate_already_existing(Request $request)
{
    $request_match = Req::findOrFail($request->input('assistanceRequestId'))->feedback()->count();

    if($request_match > 0) {
        return true;
    }
}

OR

public function rate_already_existing(Request $request)
{
    $request_match = Req::findOrFail($request->input('assistanceRequestId'))->feedback;

    if(!is_null($request_match)) {
        return true;
    }
}

edited May 13, 2020 at 10:21

answered May 13, 2020 at 10:10

Kent

1865 bronze badges

Comments

nikistag · Accepted Answer · 2020-05-13 11:13:40Z

0

Why not think the other way around? Like:

public function rate_already_existing(Request $request)
    {
        $feedback = Feedback::select('request_id')->where('request_id', $request->input('assistanceRequestId'))->first();

        if($feedback != null) {
            return true;
        }
    }

And if you want to return the request then return $feedback->request .... or something like that.

answered May 13, 2020 at 11:13

nikistag

7946 silver badges12 bronze badges

Comments

Mohamed Baklouti · Accepted Answer · 2020-05-13 11:39:24Z

0

You can change the solution

public function rate_already_existing(Request $request)
{
   $request_match = Req::find($request->input('assistanceRequestId'))->feedback;

   return empty($request_match);

}

or

public function rate_already_existing(Request $request)
{
   $request_match = Req::with('feedback')->where('id', $request->input('assistanceRequestId'))->get();

   return empty($request_match);
}

You don't need the count number, so you can check with empty

edited May 13, 2020 at 11:39

answered May 13, 2020 at 10:09

Mohamed Baklouti

12111 bronze badges

2 Comments

Michele Della Mea Over a year ago

When request_match has no rows still appears the error: Call to a member function get() on null.

Mohamed Baklouti Over a year ago

Yes, you are using "find", you don't need to use get() or count() $request_match = Req::find($request->input('assistanceRequestId'))->feedback; or Req::with('feedback') ->where('id', $request->input('assistanceRequestId')) ->get();

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