Laravel Eloquent query siblings in same table with eager loading - php

Question

I have a parent table called patients which has a one-to-many relationship with a child table called notes. (i.e. One patient can have several notes). If given a note, I would like to find other notes for the same patient. Notes are related to patients by a fk called patient_id.
In SQL, I'd do this:
SELECT * FROM notes WHERE patient_id={note.patient_id} AND id <> {note.id}
In Eloquent, I have this:
class Note extends Model
{
public function otherEncounterNotes()
{
return $this->hasMany('App\Note', 'patient_id', 'patient_id')->where('id', '<>',$this->id);
}
...
In my database, the patient with id=1 has two notes with ids 1 and 2, so if I look for the siblings of note id 1, I should get note id 2.
When I use find(), it works as expected, but when I use where(), it returns the original note instead of the sibling. Any ideas?
>>> Note::find(1)->otherEncounterNotes->pluck('id')
=> Illuminate\Support\Collection {#5542
all: [
2,
],
}
>>> Note::where('id',1)->with('otherEncounterNotes')->pluck('id')
=> Illuminate\Support\Collection {#5526
all: [
1,
],
}

Answer 1

Given a Note id, you could obtain the results you want by using the relationship with the Patient model.
$note_id = 1;
// "Pretty" syntax, but it's 3 queries
$sibling_notes = Note::find($note_id) // Query 1
->patient // Query 2
->notes()->where('id', '<>', $note_id)->pluck('id'); // Query 3
Or using a subquery
$note_id = 1;
// A bit messier, 1 query + 1 subquery
$sibling_notes = Note::where('id', '<>', $note_id)
->where('patient_id', function ($subquery) use ($note_id) {
$subquery->select('patient_id')->from('notes')->where('id', $note_id)->limit(1);
})
->pluck('id');
// PHP >= 7.4
Note::where('id', '<>', $note_id)
->where('patient_id', fn($q) => $q->select('patient_id')->from('notes')->where('id', $note_id)->limit(1))
->pluck('id');
The later, you could turn into a query scope
# Note model
public function scopeSiblingsOf($query, $note_id)
{
return $query->where('id', '<>', $note_id)
->where('patient_id', function ($subquery) use ($note_id) {
$subquery->select('patient_id')
->from('notes')
->where('id', $note_id)
->limit(1);
});
}
# Usage
Note::siblingsOf(1)->pluck('id');