laravel load candidates with given skills - php

Question

In my website users can create candidates (one-many relation) and those candidates can have skills (many-many).
User model:
public function candidates() {
return $this->hasMany(Candidate::class);
}
candidate model:
public function skills() {
return $this->belongsToMany(Skill::class, 'candidate_skill', 'candidate_id', 'skill_id');
}
Skills model:
public function candidates() {
return $this->belongsToMany(Candidate::class, 'candidate_skill', 'candidate_id', 'skill_id')
->withTimestamps();
}
I already have an index page where an user can view ALL his made candidates
$candidates = Auth::user()->candidates;
on the edit page, skills can get synced to the candidate in question
$candidate->skills()->sync(request()->skills);
and back to the index page it shows how many skills the candidates have
<td>{{count($candidate->skills)}}</td>
now, I need to make a search bar. My table already has one(dataTable) to search in the already loaded td's. But I need a search bar to search for candidates which have certain skills, say I want to search for candidates which are synced with 'css' and only show those in the table.
I read through the laravel docs and tried eager loading it:
$hasCss = $candidates->load(['skills' => function ($query) {
$query->where('name', '=', 'css');
}]);
but this just loaded all candidates with only the css skill displayed, even the candidates who dont have it. I want to only load candidates who have the skill and leave the others out.
How do I do this, I'm clueless :s

Answer 1

You're looking for whereHas(...)
Current user's candidates that have CSS skill:
$withCss = Auth::user()->candidates()->whereHas('skills', function ($q) {
$q->where('name', 'css');
})->get();

Answer 2

In your Skill Model, you have an error in your relationship definition. You wrote
public function candidates() {
return $this->belongsToMany(Candidate::class, 'candidate_skill', 'candidate_id', 'skill_id')
->withTimestamps();
}
Swap 'candidate_id' and 'skill_id'. The local foreign key always comes first.
public function candidates() {
return $this->belongsToMany(Candidate::class, 'candidate_skill', 'skill_id', 'candidate_id')
->withTimestamps();
}