$near 查询 returns 添加 $maxDistance 后有 0 个结果

Question

我有一个结构如下的数据库：

{
    "_id" : ObjectId("5785663bda7b71a0c5601c89"),
    "visible" : true,
    "created" : {
        "changeset" : "29670315",
        "user" : "samit_53",
        "version" : "1",
        "uid" : "2297171",
        "timestamp" : "2015-03-23T03:59:14Z"
    },
    "type" : "node",
    "id" : "3413812873",
    "pos" : [
        22.1173487,
        88.0034742
    ]
}

现在我在 pos 上有“2d”索引

>>db.kol_sample.getIndexes()
[
    {
        "v" : 1,
        "key" : {
            "_id" : 1
        },
        "ns" : "project_sample.kol_sample",
        "name" : "_id_"
    },
    {
        "v" : 1,
        "key" : {
            "pos" : "2d"
        },
        "ns" : "project_sample.kol_sample",
        "name" : "pos_2d"
    }
]

现在，当我只使用 $near 进行查询时，我得到了 100 个结果

db.kol_sample.findOne({"pos":{$near:[22,88]}})
{
    "_id" : ObjectId("5785663bda7b71a0c5601c89"),
    "visible" : true,
    "created" : {
        "changeset" : "29670315",
        "user" : "samit_53",
        "version" : "1",
        "uid" : "2297171",
        "timestamp" : "2015-03-23T03:59:14Z"
    },
    "type" : "node",
    "id" : "3413812873",
    "pos" : [
        22.1173487,
        88.0034742
    ]
}

但是在我添加 $maxDistance 参数后，无论我经过多远，它总是 returns null

db.kol_sample.findOne({"pos":{$near:[22.1173487,88.0034742]},$maxDistance:100})
null

MongoDB shell 版本：2.4.9 32bit

Answer 1

我使用了错误的语法，我需要在传递给 pos 的字典中传递 $maxDistance

错误

db.kol_sample.find({"pos":{$near:[22.1173487,88.0034742]},$maxDistance:100})

正确

db.kol_sample.find({pos:{$near:[22.1173487,88.0034742],$maxDistance:1/111.2}})

$near 查询 returns 添加 $maxDistance 后有 0 个结果

$near query returns 0 results after adding $maxDistance

database

indexing

geolocation

geospatial

mongodb