get all data count from relationship | Laravel - laravel

Question

i use laravel:command for function, which is i need to know how many reviews been given to my products, i will capture my database example below:
Product fields
Reviews fields
i've already declare the relationship which is:
App\Models\Product :
public function rev()
{
return $this->hasMany(Reviews::class, 'product_id', 'id');
}
App\Models\Review :
public function prod()
{
return $this->belongsTo(Products::class, 'product_id','id');
}
and this is my command for the function:
protected $signature = 'review:product {product_id}';
public function handle()
{
$id = $this->arguments('product_id');
$products = Products::with('rev')->whereId($id)->get();
foreach ($products as $key => $value) {
$rating = $value->rev->rating;
}
dd($products);
}
after i run my command it returns this error
Error
what i'm expecting is i could get the whole rating of specific id

Answer 1

You did not declare the variable $rating prior to using it.
But there is a much easier approach to your problem, since youve already setup the relationships.
public function handle()
{
$id = $this->arguments('product_id');
$products = Products::find($id);
$ratings = $products->rev->pluck('rating');
dd($ratings);
}

Answer 2

Because of product can have many revs, so you can use loop for this
foreach ($value->rev as $item) {
$val = $item->rating;
}

Answer 3

if you are expecting to sum up all rating for particular product id, then you should declare initial number for variable $rating before foreach, then sum up with += operator :
public function handle(){
$id = $this->arguments('product_id');
$products = Products::with('rev')->whereId($id)->get();
$rating = 0;
foreach ($products as $key => $value) {
$rating += $value->rev->rating;
}
dd($rating);
}