Get average with nested relationship belongs to in laravel

Question

I want to ask for you. hopefully my problem will be quickly resolved.

I have 3 tables consist of :

ads

• id

• title_ads

transaction

• id

• transaction_id

• id_ads

rating

• id
• transaction_id
• rating_value

relationship :

ads to transaction is has many

transaction to rating is belongs to

I want to ask this, how to get avg rating value from table ads? I am confused, because I think to get avg rating maybe use hasManyThrought but in this case, There is relationship belongsTo. hwo to solved it? Thank you very much :)

Answer 1

Define a hasManyThrough relation in your Ad model

class Ad extends Model
{
    /**
     * Get all ratings of an Ad.
     */
    public function ratings()
    {
        return $this->hasManyThrough('App\Rating', 'App\Transaction');
    }
}

Now you can get the ratings in your controller with the Ad model and the ratings relation

public function getRatingsAverage()
{
    // Fetch a single ad (or remove the find and get multiple)
    $ad = Ad::where('id', 1)->with('ratings')->get();

    // write average logic here...

    // could be something like this:
    $total_rating = 0;

    foreach($ad->ratings as $rating) {
        // loop through all the ratings of the ad and add the value to the total rating
        $total_rating = $total_rating + $rating->value;
    }

    // divide the total rating by the amount of ratings to get the average
    $average = $total_rating / count($ad->ratings);
}