Question

我想问你。希望我的问题能很快得到解决。

我有3个表格包括：

ID
title_ads

交易

ID
的transaction_id
id_ads

的评价

ID
的transaction_id
RATING_VALUE

关系：

广告到交易有很多

交易到评级属于

我想问一下，如何从表格广告中获得平均评分值？我很困惑，因为我认为获得平均评级可能使用hasManyThrought但在这种情况下，有关系属于。我解决了吗？非常感谢你:)）

Answer 1

在hasManyThrough模型中定义Ad关系

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

现在，您可以使用Ad模型和ratings关系

在控制器中获得评级

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);
}

Answer 2

要获得每个广告的评分，您可以通过急切加载关系来查询广告。然后，您可以循环浏览$ads并添加平均逻辑来访问交易和评级。

$ads = Ads::with('transaction.rating')->get();
//Load all ads with the transaction and rating relations
foreach($ads as $ad){
    //All transactions from the ad
    $transactions = $ad->transaction;
    foreach($transactions as $transaction){
        //The rating from the transaction
        $rating = $transaction->rating;
    }
}

嵌套关系的平均值属于laravel

2 个答案: