Laravel按关系计数变形许多组

Question

我喜欢这个模型：

class Post extends Model
{
    use HasFactory;

    protected $guarded = [];

    public function comments()
    {
        return $this->morphMany(Comment::class, 'commentable');
    }

    public function images()
    {
        return $this->morphMany(Image::class, 'imageable');
    }

    public function views()
    {
        return $this->morphMany(View::class, 'viewable'); 
    }

    public function category()
    {
        return $this->belongsTo(Category::class);
    }
}

通过这个查询我会得到帖子：

$posts = Post::query()
            ->with([
                'category',
                'images',
            ])
            ->withCount([
                'views'
            ])
            ->get();

问题：

如何汇总帖子浏览量并按类别分组以获得每个类别的总浏览量？

我可以使用这样的原始 SQL 查询获得所需的结果：

SELECT `categories`.`title` AS `category`,
    COUNT(`views`.`viewable_id`) AS `totalViews`
FROM `posts`
LEFT JOIN `categories`
    ON `categories`.`id` = `posts`.`category_id`
LEFT JOIN `views`
    ON `views`.`viewable_id` = `posts`.`id`
WHERE `views`.`viewable_type` = "App\\Models\\Post"
GROUP BY `categories`.`id`

但是如何使用 laravel eloquent 生成这样的 sql 查询并获得结果呢？

Answer 1

您可以在 $posts 集合上使用 reduce。类似于：

$categoriesCounts = $posts->reduce(static function(array $carry, Post $post) {

    $carry[$post->category_id] = ($carry[$post->category_id] ?? 0) + $post->views_count;

    return $carry;
}, []);
  

结果数组将如下所示：

array(3) {
  [1] => int(4)
  [5] => int(20)
  [6] => int(10)
}