在MongoDB中查找数组项不为null的项_Mongodb

在MongoDB中查找数组项不为null的项

mongodb

在MongoDB中查找数组项不为null的项,mongodb,Mongodb,“我的文档”的架构如下所示： history: { type: [Object] } 我想找到数组中第15位有项目的所有文档我希望能够解决的问题是： db.getCollection('teams').find({'history.15': {$exists: true}}) 但是如果history.15为空，它仍然会返回不是我想要的文档。因此，简单的解决方法应该是： db.getCollection('teams').find({'history.15': {$exists: true

“我的文档”的架构如下所示：

history: { type: [Object] }

我想找到数组中第15位有项目的所有文档

我希望能够解决的问题是：

db.getCollection('teams').find({'history.15': {$exists: true}})

但是如果

history.15

为空，它仍然会返回不是我想要的文档。因此，简单的解决方法应该是：

db.getCollection('teams').find({'history.15': {$exists: true, $ne: null}})

但这不会返回任何对象（而且我的数据库中的某些对象的第15个数组项不是null）

有没有办法让这个查询正常工作

更新：以下是我的查询未找到的示例文档：

{
    "_id" : "FR5BTtggnbxRrDqi3",
    "history" : [ 
        null, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
            ],
            "subs" : [ 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 34,
            "finalLineup" : [ 
                "47oDynBoQifNyhG9u", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "6xvdipvf8PNNgaB4d"
            ],
            "finalSubs" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "gWtx6YZW5sPehiksC", 
                "QFWQLFyLvpzvfn9Nb", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
                    "in" : "ad7z4NnoqMsLWyhpt",
                    "out" : "DmwbPcTpPKoPQqJe6"
                }, 
                {
                    "in" : "HcPjMYdG7FcxhRuFj",
                    "out" : "gWtx6YZW5sPehiksC"
                }, 
                {
                    "in" : "REs5NdgicB3wYwr8F",
                    "out" : "QFWQLFyLvpzvfn9Nb"
                }
            ]
        }, 
        {
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                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
            ],
            "subs" : [ 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 0,
            "finalLineup" : [ 
                "47oDynBoQifNyhG9u", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "6xvdipvf8PNNgaB4d", 
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                "ad7z4NnoqMsLWyhpt", 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : []
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
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                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
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                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
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                "ad7z4NnoqMsLWyhpt", 
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                "BaRu7TonDB8iKhzdC", 
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                "47oDynBoQifNyhG9u", 
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                {
                    "in" : "ad7z4NnoqMsLWyhpt",
                    "out" : "DmwbPcTpPKoPQqJe6"
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        }, 
        {
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                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
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            "score" : 38,
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                "ad7z4NnoqMsLWyhpt", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
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                "ux7HCjzSpw25JYe7r"
            ],
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                {
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                {
                    "in" : "ad7z4NnoqMsLWyhpt",
                    "out" : "DmwbPcTpPKoPQqJe6"
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        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
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            "score" : 27,
            "finalLineup" : [ 
                "ad7z4NnoqMsLWyhpt", 
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                    "out" : "DmwbPcTpPKoPQqJe6"
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                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
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                "REs5NdgicB3wYwr8F", 
                "HcPjMYdG7FcxhRuFj"
            ],
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                "gWtx6YZW5sPehiksC", 
                "QFWQLFyLvpzvfn9Nb", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
                    "in" : "HcPjMYdG7FcxhRuFj",
                    "out" : "gWtx6YZW5sPehiksC"
                }, 
                {
                    "in" : "REs5NdgicB3wYwr8F",
                    "out" : "QFWQLFyLvpzvfn9Nb"
                }
            ]
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
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            ],
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                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 14,
            "finalLineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "ux7HCjzSpw25JYe7r", 
                "HcPjMYdG7FcxhRuFj"
            ],
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                "gWtx6YZW5sPehiksC", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "QFWQLFyLvpzvfn9Nb"
            ],
            "autoSubs" : [ 
                {
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                    "out" : "gWtx6YZW5sPehiksC"
                }, 
                {
                    "in" : "ux7HCjzSpw25JYe7r",
                    "out" : "QFWQLFyLvpzvfn9Nb"
                }
            ]
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
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                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
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                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
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                "HcPjMYdG7FcxhRuFj"
            ],
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                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
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                    "out" : "gWtx6YZW5sPehiksC"
                }
            ]
        }, 
        {
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                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
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                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
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            ],
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                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
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                    "out" : "gWtx6YZW5sPehiksC"
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        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
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            "finalLineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "REs5NdgicB3wYwr8F", 
                "QFWQLFyLvpzvfn9Nb", 
                "HcPjMYdG7FcxhRuFj"
            ],
            "finalSubs" : [ 
                "gWtx6YZW5sPehiksC", 
                "47oDynBoQifNyhG9u", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
                    "in" : "HcPjMYdG7FcxhRuFj",
                    "out" : "gWtx6YZW5sPehiksC"
                }, 
                {
                    "in" : "REs5NdgicB3wYwr8F",
                    "out" : "47oDynBoQifNyhG9u"
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            ]
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
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            ]
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    ]
}

因此，为了简化答案，假设我们使用一个数组

，包含3个不同的数据位：

> db.test.find()
{ "_id" : ObjectId("585145ee8b5e4bf7a33373ee"), "a" : [ { "i" : 0 }, { "i" : 1 } ] }
{ "_id" : ObjectId("585145f68b5e4bf7a33373ef"), "a" : [ { "i" : 0 }, { "i" : 1 }, null ] }
{ "_id" : ObjectId("585146038b5e4bf7a33373f0"), "a" : [ { "i" : 0 }, { "i" : 1 }, { "i" : 2 } ] }

为了简化本例，我们将检查索引2，我们可以使用聚合框架：

var index = 2;

db.test.aggregate([
    { $project: { indexValue: { $arrayElemAt: [ '$a', index ] } } },
    { $match: { 'indexValue' : { $ne: null } } }
])

然后将输出以下内容：

{ "_id" : ObjectId("585146038b5e4bf7a33373f0"), "indexValue" : { "i" : 2 } }

这符合你的标准，但如果你这样做的话就够奇怪了

db.test.find({ 'a.2' : { $ne: null } } )

它与任何文档都不匹配，猜测这与访问数组的索引有关

无论如何，有关匹配

null

和无现有文档的更多信息，请参阅-

似乎对我有用。是否有一种方法可以添加用于测试的样本数据？仅供参考，这是一个以零为基础的指数。这对我也很有用。我想问题在于

历史记录.15

必须是

历史记录.14

。我添加了一个应该通过测试的示例文档，玩弄索引对我不起作用。