如何从 Grid Yii2 搜索模型中的许多关系中获取计数答案

【问题标题】：How to get count from many relations in a Grid Yii2 Search Model如何从 Grid Yii2 搜索模型中的许多关系中获取计数
【发布时间】：2016-12-17 12:12:02
【问题描述】：

我在模型中有很多关系。我想使用过滤器和导出网格的搜索模型在网格视图中显示订单、产品、订单的总数，但我无法弄清楚如何通过排序获得计数。我有以下关系。

public function getProducts()
{
    return $this->hasMany(Product::className(), ['user_id' => 'user_id']);
}
public function getShopImages(){
    return $this->hasMany(ShopImage::className(), ['user_id' => 'user_id']);
}
/**
 * @return \yii\db\ActiveQuery
 */
public function getOrders()
{
    // Customer has_many Order via Order.customer_id -> id
    return $this->hasMany(Order::className(), ['user_id' => 'user_id']);
}

/**
 * @return \yii\db\ActiveQuery
 */
public function getOrderrs()
{
    // Customer has_many Order via Order.customer_id -> id
    return $this->hasMany(Order::className(), ['merchant_id' => 'user_id']);
}

我需要对每一个进行计数。有什么想法，怎么做？

【问题讨论】：

标签： php gridview yii2

【解决方案1】：

你可以像这样调用方法：

$model->getProducts()->count();

这是如何工作的：

当你调用实际方法时返回一个yii\db\ActiveQueryInterface实例，所以你可以使用count()、all()、one()等方法。

通常当您访问关系时，您会像 $model->products 这样的模型类的属性一样进行操作。通过这种方式，您可以获得该方法实际返回的 yii\db\ActiveQueryInterface 的结果，使用 all() 或 one() 进行评估，具体取决于您使用的是 hasMany 还是 hasOne。

【讨论】：

【解决方案2】：

请查看以下链接。对你有帮助。

一个。 https://github.com/yiisoft/yii2/issues/2179

b. http://www.yiiframework.com/forum/index.php/topic/62772-how-to-get-count-in-relation-table-in-yii2-activerecord/

public function getProducts(){
 return $this->hasMany(Product::className(), ['user_id' => 'user_id'])->count();}

【讨论】：

【解决方案3】：

谢谢，this link from github也帮了我很多。

    +
     +## Selecting extra fields
     +
     +When Active Record instance is populated from query results, its attributes are filled up by corresponding column
     +values from received data set.
     +
     +You are able to fetch additional columns or values from query and store it inside the Active Record.
     +For example, assume we have a table named 'room', which contains information about rooms available in the hotel.
     +Each room stores information about its geometrical size using fields 'length', 'width', 'height'.
     +Imagine we need to retrieve list of all available rooms with their volume in descendant order.
     +So you can not calculate volume using PHP, because we need to sort the records by its value, but you also want 'volume'
     +to be displayed in the list.
     +To achieve the goal, you need to declare an extra field in your 'Room' Active Record class, which will store 'volume' value:
     +
     +```php
     +class Room extends \yii\db\ActiveRecord
     +{
     +    public $volume;
     +
     +    // ...
     +}
     +```
     +
     +Then you need to compose a query, which calculates volume of the room and performs the sort:
     +
     +```php
     +$rooms = Room::find()
     +    ->select([
     +        '{{room}}.*', // select all columns
     +        '([[length]] * [[width]].* [[height]]) AS volume', // calculate a volume
     +    ])
     +    ->orderBy('volume DESC') // apply sort
     +    ->all();
     +
     +foreach ($rooms as $room) {
     +    echo $room->volume; // contains value calculated by SQL
     +}
     +```
     +
     +Ability to select extra fields can be exceptionally useful for aggregation queries.
     +Assume you need to display a list of customers with the count of orders they have made.
     +First of all, you need to declare a `Customer` class with 'orders' relation and extra field for count storage:
     +
     +```php
     +class Customer extends \yii\db\ActiveRecord
     +{
     +    public $ordersCount;
     +
     +    // ...
     +
     +    public function getOrders()
     +    {
     +        return $this->hasMany(Order::className(), ['customer_id' => 'id']);
              //->from(['your_table_alias'=>Order::className()])
     +    }
     +}
     +```
     +
     +Then you can compose a query, which joins the orders and calculates their count:
     +
     +```php
     +$customers = Customer::find()
     +    ->select([
     +        '{{customer}}.*', // select all customer fields
     +        'COUNT({{order}}.id) AS ordersCount' // calculate orders count
     +    ])
     +    ->joinWith('orders') // ensure table junction
     +    ->groupBy('{{customer}}.id') // group the result to ensure aggregation function works
     +    ->all();

在你的搜索模型中，你应该这样做

class Search extends yourModel
{
    /**
     * @inheritdoc
     */
    public function rules()
    {
        return [
            your rules.......
        ];
    }

    /**
     * @inheritdoc
     */
    public function scenarios()
    {
        // bypass scenarios() implementation in the parent class
        return Model::scenarios();
    }

    /**
     * Creates data provider instance with search query applied
     *
     * @param array $params
     *
     * @return ActiveDataProvider
     */
    public function search($params)
    {
        $query = Fromto::find()->joinWith('orders')->groupBy('{{customer}}.Id');

        $dataProvider = new ActiveDataProvider([
            'query' => $query,
        ]);

        $this->load($params);

        if (!$this->validate()) {
            // uncomment the following line if you do not want to return any records when validation fails
            // $query->where('0=1');
            return $dataProvider;
        }

        $query->andFilterWhere([
            'Id' => $this->Id,
            '{{customer}}.customer_column' => $this->your_column,
        ]);

        return $dataProvider;
    }
}

在视图中

<?= GridView::widget([
    'dataProvider' => $dataProvider,
    'filterModel' => $searchModel,
    'columns' => [
        ['class' => 'yii\grid\SerialColumn'],

        'Id',
        [
            'attribute'=>'your_column',
            'label'=>'your label',
            'value'=>function($model){
                return $model->orders->order_column;
            }
        ],
        .....

        ['class' => 'yii\grid\ActionColumn'],
    ],
]); ?>

【讨论】：