How to get data with pivot data attached? - php

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.

Answer 1

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.