How to get data with pivot data attached?

Question

I'm trying to get the data from my Lists table and include an array with the ID's of the tracks in that list.

This is a sample of the database model, with a relation N:M.

In my List model, I added this method:

public function tracks()
{
   return $this->belongsToMany(Track::class, 'List_Tracks', 'id_list', 'id_track');
}

So, in my ListController, I'm doing the following:

$list = List::find($id);
$list->tracks_list = $list->tracks->pluck('track_id');
return $list;

And what I get is as many objects as tracks I have in a same list, for example:

[
{
 "id_track": 1,
 "name": "Yesterday",
 "tracks_list": [
  1,
  2
 ]
 "pivot": {
    "id_list": 1,
    "id_track": 1
 }
},
{
 "id_track": 2,
 "name": "Lucy in the sky with diamonds",
 "pivot": {
    "id_list": 1,
    "id_track": 2
 }
}
]

But what I want to get is:

{
 "id_list": 1,
 "name": "The Best of The Beatles",
 "tracks_list": [
  1,
  2
]
}

I think the things I've tried are much more complex than the proper solution.

How would you get the data in this way?

Thanks in advance.

It' seems duplicate of https://stackoverflow.com/questions/27434338/laravel-get-pivot-data-for-specific-many-to-many-relation ? — Vikash Pathak, May 25 '19 at 10:08
Possible duplicate of [Laravel: Get pivot data for specific many to many relation](https://stackoverflow.com/questions/27434338/laravel-get-pivot-data-for-specific-many-to-many-relation) — Vikash Pathak, May 25 '19 at 10:10
have you tried `List::find($id)->with('tracks');`? I think that should take data from the relation instead of pivot table. You will might need to change the call a bit = `List::with('tracks')->where('id', '=', $id)->first()`. — Silencesys, May 25 '19 at 10:12
@Silencesys That's correct, and it brings the whole object, what makes me think that perhaps I just need the ID's within an array, something like: { "id_list": 1, "name": "The Best of The Beatles", "tracks": [ 1, 2 ] } Is there any way in Laravel to do this easily? — yisus, May 27 '19 at 11:31

score 0 · Accepted Answer · answered May 27 '19 at 15:36

You need to load the relationship first and then write rest of the eloquent query, otherwise you will get only list of ids from the pivot table.

List::with('tracks')->where('id', '=', $id)->first();
// Following method should work too
List::with('tracks')->find($id);

Based on your commentary - to get only array of ids related to the list you don't need to load the relationship and can use only:

List::find($id)->tracks()->pluck('id');
// In case previous method will not work, you can try this one:
List::find($id)->tracks()->pluck('tracks.id');
// before dot should be name of the table, not relationship's.

So if you need only ids of the tracks that are attached to the playlist. I would recommend adding to your List model following method:

// App\Models\List
public function getTrackIdsAttribute()
{
    return $this->tracks->pluck('id')->toArray();
}

Then you should be able to simply call List::find($id)->trackIds to get all ids of tracks attached to the given list. If you're not sure why I am defining the method as getTrackIdsAttribute and call only trackIds on the model, take a look at Eloquent: Mutators.

How to get data with pivot data attached?

1 Answers1