Laravel 5 Model::with() behavior - php

Question

I'm trying to get a simple list of products with a given category, using Laravel 5's (L5) Model::with() method. But it seems that L5 ignores the category where clause.
The relation in my Product model:
public function categories(){
return $this->belongsToMany('App\Category', 'categories_products');
}
In my Controller:
public function getByCategory($slug){
$return = Product::with(array('categories' => function($query) use ($slug){
$query->where('slug', 'like', $slug);
}))->paginate(60);
dd($return);
}
The result is a list of every product in my database, instead of just a list of those with the given category slug.
I'v tried to hardcode in some different where clauses, but all seems to be ignored. Am I missing something?

Answer 1

Eloquent doesn't use joins to query related data when using with(), but instead uses separate queries. In your example, it first fetches products and then fetches related categories.
You need to use has() or whereHas() to return only those products that have categories (slugs?).
public function getByCategory($slug){
$return = Product::has('categories')->with(array('categories' => function($query) use ($slug){
$query->where('slug', 'like', $slug);
}))->paginate(60);
dd($return);
}
Or:
public function getByCategory($slug){
$return = Product::whereHas('categories', function($query) use ($slug){
$query->where('slug', 'like', $slug);
})->paginate(60);
dd($return);
}
whereHas() adds a subquery that counts the number of relations. You should use DB::getQueryLog() to see the SQL that Eloquent produces. Makes it a lot easier to figure out what's going on!

Answer 2

Do you need to have an advanced subquery? If slug is defined as a column in product you can do this:
$return = Product::where('slug', 'like', $slug)->paginate(60);
dd($return);
Or if using the relations your query would look like this:
$return = Product::where('slug', 'like', $slug)->categories->paginate(60);
dd($return);