每个结果行 Laravel 5 sub-query

Question

我对 Eloquent 和 Laravel 5 比较陌生，我正在使用查询构建器根据向函数提供的变量来创建类别动态查询。

在我的类别 table 中有一个名为 'parent_id' 的列，它指示类别是否为 sub-category。到目前为止，这是我的功能：

public static function filterCategory($vars) {

        $query = Category::query();

        if((array_key_exists('order_by', $vars)) && (array_key_exists('order', $vars))) {
            $query = $query->orderBy($vars['order_by'], $vars['order']);
        }

        if(array_key_exists('product', $vars)) {
            $query = $query->whereHas('products', function($q) use ($vars){
                return $q->where('id', $vars['product']);
            });
        }

        if(array_key_exists('sub_cats', $vars)) {
            $query = $query->with('subCategories');
        }

        return $query->get();
    }

我在名为 getChildren 的类别模型上创建了一个函数，如下所示：

public function subCategories() {
    return $this->hasMany('App\Category', 'parent_id', 'id');
}

我想要做的是当我的类别函数被调用到 return 类别时，我需要为每一行执行一个 sub-query，这将创建一个 sub-array 结果 object 包含所有类别，这些类别具有当前类别的 ID，因为它是 'parent_id'。我想要这个 returned:

[
  {
    "id": "1",
    "name": "Dr. Ben Becker DDS",
    "description": "Et atque illo ut architecto. Blanditiis laboriosam hic sed quia. Aperiam quis totam distinctio.",
    "created_at": "1981-04-07 22:04:40",
    "updated_at": "2009-02-26 19:53:09",
    "parent_id": null,
    "subcategories" : {
         //results in here
     }
  },
  {
    "id": "2",
    "name": "Ms. Winona Lehner",
    "description": "Repudiandae nostrum repellendus nulla delectus saepe sapiente ipsam. Delectus voluptatem quis excepturi. Tenetur nostrum et cum quia. Fugiat totam sed dicta totam illo ut dolores.",
    "created_at": "2002-01-13 13:42:18",
    "updated_at": "1981-10-25 11:39:14",
    "parent_id": null,
    "subcategories" : {
         //results in here
     }
  },

现在，这对我来说在 vanilla PHP 和 MYSQL 中很简单，但我不知道如何在 Laravel 中使用 Eloquent查询生成器。

**更新所以我有子类别 returning 但不幸的是不正确。这是我的输出：

[
  {
    "id": "1",
    "name": "Dr. Ben Becker DDS",
    "description": "Et atque illo ut architecto. Blanditiis laboriosam hic sed quia. Aperiam quis totam distinctio.",
    "created_at": "1981-04-07 22:04:40",
    "updated_at": "2009-02-26 19:53:09",
    "parent_id": null,
    "sub_categories": [
      {
        "id": "3",
        "name": "Dr. Manuel Medhurst",
        "description": "Pariatur ut corporis quas sequi dolor totam. Nisi ad amet velit reiciendis voluptates dolore aperiam. Impedit perferendis et a.",
        "created_at": "1998-09-20 07:40:23",
        "updated_at": "2002-04-01 18:41:24",
        "parent_id": "1"
      },
      {
        "id": "4",
        "name": "Lee Monahan",
        "description": "Nihil qui quod voluptatem non accusamus voluptas. Non et quae velit delectus consequatur vel. Qui totam non rerum sunt nisi soluta sequi. Consequatur eaque quia delectus qui assumenda.",
        "created_at": "2014-11-24 06:31:10",
        "updated_at": "1996-03-28 18:58:55",
        "parent_id": "1"
      },
      {
        "id": "5",
        "name": "Miller Osinski",
        "description": "Itaque et sed voluptatem earum nulla eligendi tenetur. Et velit ut voluptas similique. Autem rerum sapiente voluptatibus optio esse qui sit et. Alias eligendi aut quibusdam inventore.",
        "created_at": "2011-10-08 18:16:56",
        "updated_at": "1996-09-29 16:29:37",
        "parent_id": "1"
      }
    ]
  },
  {
    "id": "3",
    "name": "Dr. Manuel Medhurst",
    "description": "Pariatur ut corporis quas sequi dolor totam. Nisi ad amet velit reiciendis voluptates dolore aperiam. Impedit perferendis et a.",
    "created_at": "1998-09-20 07:40:23",
    "updated_at": "2002-04-01 18:41:24",
    "parent_id": "1",
    "sub_categories": []
  },
  {
    "id": "4",
    "name": "Lee Monahan",
    "description": "Nihil qui quod voluptatem non accusamus voluptas. Non et quae velit delectus consequatur vel. Qui totam non rerum sunt nisi soluta sequi. Consequatur eaque quia delectus qui assumenda.",
    "created_at": "2014-11-24 06:31:10",
    "updated_at": "1996-03-28 18:58:55",
    "parent_id": "1",
    "sub_categories": []
  },
  {
    "id": "5",
    "name": "Miller Osinski",
    "description": "Itaque et sed voluptatem earum nulla eligendi tenetur. Et velit ut voluptas similique. Autem rerum sapiente voluptatibus optio esse qui sit et. Alias eligendi aut quibusdam inventore.",
    "created_at": "2011-10-08 18:16:56",
    "updated_at": "1996-09-29 16:29:37",
    "parent_id": "1",
    "sub_categories": []
  },
  {
    "id": "2",
    "name": "Ms. Winona Lehner",
    "description": "Repudiandae nostrum repellendus nulla delectus saepe sapiente ipsam. Delectus voluptatem quis excepturi. Tenetur nostrum et cum quia. Fugiat totam sed dicta totam illo ut dolores.",
    "created_at": "2002-01-13 13:42:18",
    "updated_at": "1981-10-25 11:39:14",
    "parent_id": null,
    "sub_categories": []
  }
]

起初这看起来是正确的，但在我的 table 中，类别 1 只有 1 child（类别 4），类别 2 应该只有 2 children（第 3 和 5 行） .似乎所有这些 sub-categories 都被错误地放入了第 1 行的子类别数组中？

谢谢

Answer 1

在你的 Category 模型中添加一个关系到它自己，就像这样：

public function subcategories()
{
    return $this->hasMany('App\Category', 'parent_id', 'id');
}

如果不是 App，请更改您的 Category 模型命名空间。

然后你就可以这样查询它们了：

$categories = Category::with('subcategories')->get();

如果需要也可以按parent_id分组排列：$categories->groupBy( 'parent_id' )->toJson();

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