Php 如何在Laravel雄辩的Jensseger Mongodb中使用Get On Eager loaded属性

我正在用拉威尔和詹塞格斯·蒙戈德雄辩。当我尝试使用get（[…]）或distinct（“…”）时，它在结果中给出空值。如何使用get（[eager\u-loaded\u-attribute\u here]）只获取一个被eager-loaded的给定属性

例如：

Message::with(['sender','receiver'])
    ->where('sender_id', '=', Auth::user()->_id)
    ->orWhere('receiver_id', '=', Auth::user()->_id)
    ->orderBy($request->orderBy, $request->orderByDirection)
    ->skip(intval($request->offset))
    ->take(intval($request->limit))
    ->get()

给出：

[
    {
        "_id": "5abc2ba193782d24996aefda",
        "receiver_id": "5abc28bd93782d235238c162",
        "text": "Hello!",
        "sender_id": "5abc2b8b93782d24996aefd8",
        "updated_at": "2018-03-28 23:56:17",
        "created_at": "2018-03-28 23:56:17",
        "sender": {
            "_id": "5abc2b8b93782d24996aefd8",
            "name": "Test 5",
            "updated_at": "2018-03-29 00:05:48",
            "created_at": "2018-03-28 23:55:55"
        },
        "receiver": {
            "_id": "5abc28bd93782d235238c162",
            "name": "Test 1",
            "updated_at": "2018-04-20 13:26:00",
            "created_at": "2018-03-28 23:43:57"
        }
    },
...
]

[
    {
        "_id": "5abc2ba193782d24996aefda",
        "sender": null,
        "receiver": null
    },
...
]

[
    {
        "0": "5abc2b8b93782d24996aefd8",
        "sender": null,
        "receiver": null
    }
]

但是使用get：

Message::with(['sender','receiver'])
    ->where('sender_id', '=', Auth::user()->_id)
    ->orWhere('receiver_id', '=', Auth::user()->_id)
    ->orderBy($request->orderBy, $request->orderByDirection)
    ->skip(intval($request->offset))
    ->take(intval($request->limit))
    ->get(['sender'])

给出：

[
    {
        "_id": "5abc2ba193782d24996aefda",
        "receiver_id": "5abc28bd93782d235238c162",
        "text": "Hello!",
        "sender_id": "5abc2b8b93782d24996aefd8",
        "updated_at": "2018-03-28 23:56:17",
        "created_at": "2018-03-28 23:56:17",
        "sender": {
            "_id": "5abc2b8b93782d24996aefd8",
            "name": "Test 5",
            "updated_at": "2018-03-29 00:05:48",
            "created_at": "2018-03-28 23:55:55"
        },
        "receiver": {
            "_id": "5abc28bd93782d235238c162",
            "name": "Test 1",
            "updated_at": "2018-04-20 13:26:00",
            "created_at": "2018-03-28 23:43:57"
        }
    },
...
]

[
    {
        "_id": "5abc2ba193782d24996aefda",
        "sender": null,
        "receiver": null
    },
...
]

[
    {
        "0": "5abc2b8b93782d24996aefd8",
        "sender": null,
        "receiver": null
    }
]

同样，在使用distinct时：

$correspondants=Message::with(['sender','receiver'])
    ->distinct('sender_id')
    ->where('sender_id', '=', Auth::user()->_id)
    ->orWhere('receiver_id', '=', Auth::user()->_id)
    ->orderBy($request->orderBy, $request->orderByDirection)
    ->skip(intval($request->offset))
    ->take(intval($request->limit))
    ->get()
    ->toArray();

给出：

[
    {
        "_id": "5abc2ba193782d24996aefda",
        "receiver_id": "5abc28bd93782d235238c162",
        "text": "Hello!",
        "sender_id": "5abc2b8b93782d24996aefd8",
        "updated_at": "2018-03-28 23:56:17",
        "created_at": "2018-03-28 23:56:17",
        "sender": {
            "_id": "5abc2b8b93782d24996aefd8",
            "name": "Test 5",
            "updated_at": "2018-03-29 00:05:48",
            "created_at": "2018-03-28 23:55:55"
        },
        "receiver": {
            "_id": "5abc28bd93782d235238c162",
            "name": "Test 1",
            "updated_at": "2018-04-20 13:26:00",
            "created_at": "2018-03-28 23:43:57"
        }
    },
...
]

[
    {
        "_id": "5abc2ba193782d24996aefda",
        "sender": null,
        "receiver": null
    },
...
]

[
    {
        "0": "5abc2b8b93782d24996aefd8",
        "sender": null,
        "receiver": null
    }
]

使用以下命令：

->get()->pluck('sender');

如果需要查询生成器：

$senderIds = Message::distinct('sender_id')
    ->where('sender_id', '=', Auth::user()->_id)
    [...]
    ->pluck('sender_id');
$senders = Sender::whereKey($senderIds)
    [...]
    ->get();

---

你想达到什么目的？@JonasStaudenmeir我想选择一个渴望加载的字段。我只需要返回发送者，所以理想情况下我希望从其父对象“取消嵌套”发送者，并且只返回发送者数组。。。理想情况下，我还希望能够对发送者执行进一步的查询，就像SQLSelect（投影）一样。但当我在一个急切加载的字段上使用select时，我只得到null。。。是否有其他方法可以获取返回querybuilder的（…），以便我可以继续链接进一步的查询？谢谢。如果你不需要

接收者
，你应该只使用
和（'sender'）
@JonasStaudenmeir是的，但这只是为了表明出于某种原因，其他急切加载的字段会受到影响。。。在这种情况下，我希望只得到sender字段，但由于某种原因，得到了两个带空值的急切加载字段…太好了，有没有办法让它返回querybuilder，这样我就可以继续链接查询（例如orderBy、take等）？我扩展了我的答案。非常感谢。。。这对大型收藏安全吗？它似乎正在获取所有发送者id，如果在第一个查询（SenderID）上执行take/limit，这将是安全的，但我认为如果存在大量SenderID（例如：10m），并且需要在第二个查询（对于$senders）中执行take/limit，而不是在第一个查询中执行第一个，这将是相当不安全的
表示您的
take（）
和
skip（）
调用等。我只想保持简短，并将重点放在相关部分。