Laravel if请求不为空,添加或位置

public function index(Request $request) {
    if ($request->has('deleted')) {
        $assistants = Assistant::onlyTrashed()->where(1);
        if ($request->has('firstName'))
            $assistants = $assistants->orWhere('firstname', 'LIKE', $request->firstName.'%');
        if ($request->has('lastName'))
            $assistants = $assistants->orWhere('lastname', 'LIKE', $request->lastName.'%');
        if ($request->has('email'))
            $assistants = $assistants->orWhere('email', 'LIKE', $request->email.'%');
    } else {
        $assistants = Assistant::all()->where(1);
        if ($request->has('firstName'))
            $assistants = $assistants->orWhere('firstname', 'LIKE', $request->firstName.'%');
        if ($request->has('lastName'))
            $assistants = $assistants->orWhere('lastname', 'LIKE', $request->lastName.'%');
        if ($request->has('email'))
            $assistants = $assistants->orWhere('email', 'LIKE', $request->email.'%');
    }

    return $this->showAll($assistants);
}

我试图检查firstname、lastname或email是否不为空,使用like命令添加到查询中。

但它返回一个错误:

类型错误:函数的参数太少 照明\支持\集合::Where(),1传递

在Laravel 5.6.