Laravel：“强制”查询生成器返回空列表

Question

我有以下路线：Route::apiResource('payments', 'PaymentController', ['except' => ['store', 'destroy']]);Route::get('users/{user}/payments', [    'as' => 'users.payments',    'uses' => 'PaymentController@index',]);这个控制器：class PaymentController{    public function index(Request $request, User $user)    {        // Initialize query builder        $query = Payment::query();        // If a user was provided, return all payments belonging to that user        // if condition is satisfied        if ($user) {            if (condition) {                $query = $customer->payments();            } else {                // Some code that causes no results                $query->whereNull('id');   // <----- This hits the database            }        }        return PaymentResource::collection($query->paginate(10));    }}如果您点击它，则应返回所有用户进行的所有付款。/payments如果命中它，则仅当为 true 时，它才应返回用户进行的所有付款，否则应返回空列表。/users/id/paymentscondition此代码有效，但是是实际命中数据库的解决方法。$query->whereNull('id');有没有办法避免命中数据库并仍然返回空列表？

Answer 1

您可以避免命中数据库，但仍然使用初始化的变量返回空列表到空集合或数组

class PaymentController

{

    public function index(Request $request, User $user)

    {

        // Initialize query builder

        $query = Payment::query();

        // If a user was provided, return all payments belonging to that user

        // if condition is satisfied

        $return = collect();

        if ($user) {

            if (condition) {

                $return = $customer->payments()->paginate(10);

            } 

        }

        return PaymentResource::collection($return);

    }

}

Answer 2

我试图在函数中有一个单一的返回，但更容易遵循@Chin梁给出的建议（谢谢！

class PaymentController

{

    public function index(Request $request, User $user)

    {

        // Initialize query builder

        $query = Payment::query();

        // If a user was provided, return all payments belonging to that user

        // if condition is satisfied

        if ($user) {

            if (condition) {

                $query = $customer->payments();

            } else {

                // Some code that causes no results

                return PaymentResource::collection(collect());

            }

        }

        // Other code here, for example a where statement

        // depending on what is passed in $request

        return PaymentResource::collection($query->paginate(10));

    }

}