Laravel雄辩地获得关系计数 [英] Laravel eloquent get relation count

问题描述

我使用Laravel 5.3.

I use Laravel 5.3.

我有2张桌子:

Articles
---------
id
cat_id
title

还有

Category
---------
id
parent_id
title

我已经在模型中定义了我的关系:

I have defined my relations in my models :

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

// Category model
public function children() 
{
    return $this->hasMany(Category::class, 'parent_id', 'id');
}   

是否有使用Eloquent的简单方法来列出带有文章计数的类别.困难之处在于，我想对 id_parent = 0 的类别进行分组，即，我只想显示带有孩子文章数的父类别.

Is there an easy way using Eloquent to have a list a categories with count of articles. The difficulty is that I want to group categories where id_parent = 0, i.e. I want to display only parent categories with count of articles in children.

我尝试过类似的事情:

    $category = new \App\Models\Category();
    $categoryTable = $category->getTable();

    return $category->leftJoin('article', 'article.cat_id', '=', 'category.id')
        ->whereIn('article.cat_id', function($query)
            {
                $query->select('cat_id')
                    ->from('categories')
                    ->where('categories.parent_id', ???)
                    ->orWhere($this->tableName .'.cat_id', $id);
            })
        ->groupBy('cat_id');

但是我迷路了...

推荐答案

您可以使用 withCount().从5.3版本开始可用

you can use withCount(). It is available from 5.3 version

有关口才访问的更多信息: https://laravel.com/docs/5.3/eloquent关系

for more info about eloquent visit : https://laravel.com/docs/5.3/eloquent-relationships

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