laravel范围模型功能错误

Question

我正在尝试使用 laravel 中的范围来汇总属于特定 cash_sale 的所有 cash_sales_items。问题是当我在这些表中有一些信息时，代码可以正常工作，但是当表为空时，我得到一个错误

Object of class Illuminate\Database\Eloquent\Builder could not be converted to string  

下面是代码和表结构

accessories_cash_salesmysql> describe accessories_cash_sales;
+---------------+------------------+------+-----+---------+----------------+
| Field         | Type             | Null | Key | Default | Extra          |
+---------------+------------------+------+-----+---------+----------------+
| id            | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| client        | varchar(255)     | NO   |     |         |                |
| exchange_rate | int(11)          | NO   |     | 0       |                |
| employee_id   | int(10) unsigned | NO   | MUL | NULL    |                |
| status        | varchar(255)     | NO   |     |         |                |
| tax           | varchar(255)     | NO   |     |         |                |
| created_at    | timestamp        | YES  |     | NULL    |                |
| updated_at    | timestamp        | YES  |     | NULL    |                |
+---------------+------------------+------+-----+---------+----------------+

另一个是

mysql> describe accessories_cash_sales_items;
+--------------------------+------------------+------+-----+---------+----------------+
| Field                    | Type             | Null | Key | Default | Extra          |
+--------------------------+------------------+------+-----+---------+----------------+
| id                       | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| accessories_id           | int(10) unsigned | NO   | MUL | NULL    |                |
| quantity                 | int(11)          | NO   |     | 0       |                |
| amount                   | int(11)          | NO   |     | 0       |                |
| accessories_cash_sale_id | int(10) unsigned | NO   | MUL | NULL    |                |
| created_at               | timestamp        | YES  |     | NULL    |                |
| updated_at               | timestamp        | YES  |     | NULL    |                |
+--------------------------+------------------+------+-----+---------+----------------+

我在刀片模板中调用范围方法

\App\AccessoriesCashSale::paidOrCollected()

在现金销售模式中，paidOrCollected 函数看起来像

public function scopePaidOrCollected($query){
    $amount = 0;
    $items = $query->where('status', '=', 'paid')->orWhere('status', '=', 'Collected')->whereMonth('created_at','=', date('m'))->get();

    foreach($items as $item){
        $amount = $amount + $item->accessoriesCashSalesItems()->sum('amount');;
    }

    return $amount;
}

Answer 1

在使用范围时，您应该始终返回修改后的查询对象。

public function scopePaidOrCollected($query){
    return $query->where('status', '=', 'paid')->orWhere('status', '=', 'Collected')->whereMonth('created_at','=', date('m'));
}

使用您的范围过滤您的查询结果，然后将其传递给范围之外的另一个方法来迭代您的集合并计算出您的数量。

编辑

您可以简单地在模型中添加另一个方法来处理您的范围数据，如下所示：

public function getCashSaleAmounts()
{
    $items = AccessoriesCashSale::paidOrCollected()->get();
    $amount = 0;

    foreach($items as $item){
        $amount += $item->accessoriesCashSalesItems()->sum('amount');
    }

    return $amount;
}

但是，您可能希望在尝试循环之前检查结果。