Php 存储在同一集合中的数组的MongoDB$in运算符

如果我有以下模式：

users = {
  _id: MongoID
  name: String,
  email: String,
  password: String,
  online: Boolean,       // Tells if user is online or not
  friends: Array,        // Storing _ids of friends
  request: Array
}

现在，我想得到所有在线朋友的名字，按名字排序

MongoDB数据库：

{
    "_id" : ObjectId("572e43d71ccbdd080f00002b"),
    "name" : "Bot 3",
    "email" : "bot3@gmail.com",
    "password" : "202cb962ac59075b964b07152d234b70",
    "online" : false,
    "friends" : [
        ObjectId("572efe481ccbdd9c12000029")
    ],
    "requests" : []
}
{
    "_id" : ObjectId("572efe481ccbdd9c12000029"),
    "name" : "Bot 4",
    "email" : "bot4@gmail.com",
    "password" : "202cb962ac59075b964b07152d234b70",
    "online" : false,
    "friends" : [
        ObjectId("573074e81ccbddc816000029"),
        ObjectId("572e43d71ccbdd080f00002b")
    ],
    "requests" : [ ]
}
{
    "_id" : ObjectId("573074e81ccbddc816000029"),
    "name" : "Bot 5",
    "email" : "bot5@gmail.com",
    "password" : "202cb962ac59075b964b07152d234b70",
    "online" : true,
    "friends" : [
        ObjectId("572efe481ccbdd9c12000029")
    ],
    "requests" : [ ]
}

我想问一些问题，比如：

var arr = db.users.find({"_id": ObjectId("572efe481ccbdd9c12000029")},
          {"friends": 1, "_id": 0});

db.users.find({$in: arr["friends"]}, {"name": 1, "online": 1}).sort({"name": 1});

我在上面的示例中尝试了这段php代码（甚至不符合要求）：

但我知道它不能满足需要。这就是我请求帮助的原因

我不熟悉使用php的MongoDB

---

提前非常感谢您的帮助。

好了，伙计们，我想了想才找到了解决方案

$cursor1 = $users->find(
array(
    "_id" => new MongoID($id),
),
array(
    "friends" => 1
)
);
$cursor1->next();
$doc1 = $cursor1->current();
$friend_arr = $doc1['friends'];

$cursor2 = $users->find(
    array(
        "_id"=> array(
            '$in' => $friend_arr
        )
    ),
    array(
        "name" => 1
    )
);
$cursor2->sort(array("name"=>1));


foreach($cursor2 as $doc2){
    echo "<div>".$doc2['name']."</div>";
}

$cursor1=$users->find(
排列(
“_id”=>新MongoID（$id），
),
排列(
“朋友”=>1
)
);
$cursor1->next（）；
$doc1=$cursor1->current（）；
$friend_arr=$doc1['friends']；
$cursor2=$users->find(
排列(
“_id”=>数组(
“$in”=>$friend\u arr
)
),
排列(
“名称”=>1
)
);
$cursor2->排序（数组（“名称”=>1））；
foreach（$cursor2作为$doc2）{
回显“$doc2['name']”；
}

此代码工作正常。我在发布前测试了它

$cursor1 = $users->find(
array(
    "_id" => new MongoID($id),
),
array(
    "friends" => 1
)
);
$cursor1->next();
$doc1 = $cursor1->current();
$friend_arr = $doc1['friends'];

$cursor2 = $users->find(
    array(
        "_id"=> array(
            '$in' => $friend_arr
        )
    ),
    array(
        "name" => 1
    )
);
$cursor2->sort(array("name"=>1));


foreach($cursor2 as $doc2){
    echo "<div>".$doc2['name']."</div>";
}