Laravel Eloquent：动态模型表获取数据

Question

试图建立一个在多个不同表中使用的Eloquent模型。以下是我的表格列表：

• 交易
• transaction201806
• transaction201807
• transaction201808

交易模型：

class Transaction extends Model
{
    protected $table = 'transaction';

    public function __construct($attributes = [], $date = null) {
        parent::__construct($attributes);
        $date = $date ?: "";
        $this->setTable("transaction$date");
    }

    public function Receipt(){
        return $this->belongsTo('App\Receipt');
    }
}

收据模型：

class Receipt extends Model
{
    protected $table = 'receipt';

    public function transaction($date = null){
        $transModel = new Transaction([], $date);
        return $this->hasMany($transModel);
    }  
}

控制器：

$date = $request->date;
$newTableName = "transaction".$date;
$transModel = new Transaction([], $date);
$query = $transModel->selectRaw($newTableName.'.*, SUM('.$newTableName.'.amount) as amount')
            ->where($newTableName.'.user_id', $user->id)
            ->with('receipt.transaction')
            ->paginate($paginate);

当没有输入时，$ date = null，结果->数据如下（这是我想要的）：

{
    "id": 2005533,
    "user_id": 12,
    "receipt_id": "1002767",
    "amount": "10.00000000",
    "type": 2,
    "created_at": "2018-12-18 11:57:22",
    "receipt": {
        "id": 1002767,
        "remark": null,
        "created_at": "2018-12-18 11:57:22",
        "transaction": [
            {
                "id": 2005532,
                "user_id": 12,
                "receipt_id": "1002767",
                "amount": "-10.00000000",
                "type": 1,
                "created_at": "2018-12-18 11:57:22",
            },
            {
                "id": 2005533,
                "user_id": 12,
                "receipt_id": "1002767",
                "amount": "10.00000000",
                "type": 2,
                "created_at": "2018-12-18 11:57:22",
            }
        ]
    }
},

当输入为201806时，$ date =“ 201806”，结果：

{
    "id": 152,
    "user_id": 12,
    "receipt_id": "100",
    "amount": "10.00000000",
    "type": 2,
    "created_at": "2018-06-10 11:57:22",
    "receipt": {
        "id": 100,
        "remark": null,
        "created_at": "2018-06-10 11:57:22",
        "transaction": []
    }
},

我现在面临的问题是$ date不为null时，我得到的结果是缺少收据交易。我可以知道该怎么做，以便在加载多个关系时知道应该指向哪个表吗？

$ date的预期结果！= null：

{
    "id": 152,
    "user_id": 12,
    "receipt_id": "100",
    "amount": "10.00000000",
    "type": 2,
    "created_at": "2018-06-10 11:57:22",
    "receipt": {
        "id": 100,
        "remark": null,
        "created_at": "2018-06-10 11:57:22",
        "transaction": [
            {
                "id": 2005532,
                "user_id": 12,
                "receipt_id": "100",
                "amount": "-10.00000000",
                "type": 1,
                "created_at": "2018-06-10 11:57:22",
            },
            {
                "id": 152,
                "user_id": 12,
                "receipt_id": "100",
                "amount": "10.00000000",
                "type": 2,
                "created_at": "2018-06-10 11:57:22",
            }
        ]
    }
},