基于关系获取集合中Laravel模型的列表和计数

Question

我有两个Laravel雄辩的模型，Product和ProductCategory，从产品到ProductCategory之间有一个名为Category（）的belongsTo（）关系。

我已经让模型集合在显示刀片中的@foreach循环中迭代，但希望能够根据类别（）关系获得产品数量的计数。。。

IE：在集合中20个模型的结果集中，可能有5个电机、5个齿轮箱和5个Acme小部件。我试图找到一种方法来输出作为结果一部分返回的类别列表，以及与每个返回类别相关的记录数。

产品模型

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Product extends Model {
/**
 * The table associated with the model.
 *
 * @var string
 */
protected $table = 'products';


/**
 * The primary key associated with the table.
 *
 * @var string
 */
protected $primaryKey = 'id';


/**
 * Indicates if the IDs are auto-incrementing.
 *
 * @var bool
 */
public $incrementing = true;


/**
 * All related features for the current model.
 */
public function features() {
    return $this->hasMany('App\ProductFeature');
}


/**
 * Created By Relationship
 */
public function created_by() {
    return $this->belongsTo('App\User');
}


/**
 * Modified By Relationship.
 */
public function modified_by() {
    return $this->belongsTo('App\User');
}


/**
 * Category Relationship.
 */
public function category() {
    return $this->belongsTo('App\ProductCategory', 'category_id', 'id');
}





/**
 * Images Relationship.
 */
public function images() {
    return $this->HasMany('App\ProductImage', 'product_id', 'id');
}


/**
 * The relations to eager load on every query.
 *
 * @var array
 */
protected $with = ['features', 'created_by', 'modified_by', 'images'];
}

产品类别模型

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class ProductCategory extends Model {
/**
 * The table associated with the model.
 *
 * @var string
 */
protected $table = 'product_categories';


/**
 * The primary key associated with the table.
 *
 * @var string
 */
protected $primaryKey = 'id';


/**
 * Indicates if the IDs are auto-incrementing.
 *
 * @var bool
 */
public $incrementing = true;


/**
 * All related features for the current model.
 */
public function products() {
    return $this->hasMany('App\Product', 'category_id', 'id');
}


/**
 * Created By Relationship
 */
public function created_by() {
    return $this->belongsTo('App\User');
}


/**
 * Modified By Relationship.
 */
public function modified_by() {
    return $this->belongsTo('App\User');
}

}

控制器方法

public function showCategory($catAlias) {
    $products= Product::all();

    return view("website.store.results", ["products" => $products]);
}

期望输出示例

Category | Count
=================
Cat 1    |   4
Cat 2    |   1
Cat 5    |   5

Answer 1

您可能希望返回类别而不是产品。您可以使用方法with Count急切地加载关系的计数：

public function someMethod()
{
    return view('someview', [
        'categories' => Category::withCount('products')->get(),
    ]);
}

@foreach ($categories as $category)
  <tr>
    <td>{{ $category->name }}</td>
    <td>{{ $category->products_count }}</td>
  </tr>
@endforeach

Laravel 6.x文档-雄辩-关系-计数相关模型withCount

我不会一次返回所有产品，但是如果你这样做了，你可以按category_id分组，然后做一个计数，如果你必须的话。

return view('someview', [
    'products' => Product::with('category:id,name')->get(),
]);

然后在你需要计数的一边：

@foreach ($products->groupBy('category_id') as $group)
  <tr>
    <td>{{ $group->first()->category->name }}</td>
    <td>{{ $group->count() }}</td>
  </tr>
@endforeach

或者，您可以返回产品查询，并使用另一个查询对类别进行计数。