Question

我的文档的架构是这样的：

history: { type: [Object] }

我想找到所有在数组中第15个点都有项目的文档。

我希望可以使用的查询是：

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

但如果history.15为null，它仍将返回不是我想要的文档。所以简单的解决方法应该是：

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

但是这不会返回任何对象（并且我的数据库中有一些对象具有非空的第15个数组项。）

任何想法如何让这个查询起作用？

更新：以下是我的查询找不到的示例文档：

{
    "_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"
                }
            ]
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
            ],
            "subs" : [ 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 0,
            "finalLineup" : [ 
                "47oDynBoQifNyhG9u", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "BaRu7TonDB8iKhzdC", 
                "DmwbPcTpPKoPQqJe6", 
                "MtZQjZqwptcY4MJXm", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
            ],
            "finalSubs" : [ 
                "ad7z4NnoqMsLWyhpt", 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : []
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
            ],
            "subs" : [ 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 18,
            "finalLineup" : [ 
                "ad7z4NnoqMsLWyhpt", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "REs5NdgicB3wYwr8F", 
                "HcPjMYdG7FcxhRuFj"
            ],
            "finalSubs" : [ 
                "gWtx6YZW5sPehiksC", 
                "QFWQLFyLvpzvfn9Nb", 
                "DmwbPcTpPKoPQqJe6", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
                    "in" : "HcPjMYdG7FcxhRuFj",
                    "out" : "gWtx6YZW5sPehiksC"
                }, 
                {
                    "in" : "REs5NdgicB3wYwr8F",
                    "out" : "QFWQLFyLvpzvfn9Nb"
                }, 
                {
                    "in" : "ad7z4NnoqMsLWyhpt",
                    "out" : "DmwbPcTpPKoPQqJe6"
                }
            ]
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
            ],
            "subs" : [ 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 38,
            "finalLineup" : [ 
                "ad7z4NnoqMsLWyhpt", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "REs5NdgicB3wYwr8F", 
                "HcPjMYdG7FcxhRuFj"
            ],
            "finalSubs" : [ 
                "gWtx6YZW5sPehiksC", 
                "QFWQLFyLvpzvfn9Nb", 
                "DmwbPcTpPKoPQqJe6", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
                    "in" : "HcPjMYdG7FcxhRuFj",
                    "out" : "gWtx6YZW5sPehiksC"
                }, 
                {
                    "in" : "REs5NdgicB3wYwr8F",
                    "out" : "QFWQLFyLvpzvfn9Nb"
                }, 
                {
                    "in" : "ad7z4NnoqMsLWyhpt",
                    "out" : "DmwbPcTpPKoPQqJe6"
                }
            ]
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
            ],
            "subs" : [ 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 27,
            "finalLineup" : [ 
                "ad7z4NnoqMsLWyhpt", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "REs5NdgicB3wYwr8F", 
                "HcPjMYdG7FcxhRuFj"
            ],
            "finalSubs" : [ 
                "gWtx6YZW5sPehiksC", 
                "QFWQLFyLvpzvfn9Nb", 
                "DmwbPcTpPKoPQqJe6", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
                    "in" : "HcPjMYdG7FcxhRuFj",
                    "out" : "gWtx6YZW5sPehiksC"
                }, 
                {
                    "in" : "REs5NdgicB3wYwr8F",
                    "out" : "QFWQLFyLvpzvfn9Nb"
                }, 
                {
                    "in" : "ad7z4NnoqMsLWyhpt",
                    "out" : "DmwbPcTpPKoPQqJe6"
                }
            ]
        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
                "gWtx6YZW5sPehiksC"
            ],
            "subs" : [ 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 34,
            "finalLineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "REs5NdgicB3wYwr8F", 
                "HcPjMYdG7FcxhRuFj"
            ],
            "finalSubs" : [ 
                "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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                "HcPjMYdG7FcxhRuFj", 
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                "ad7z4NnoqMsLWyhpt", 
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            ],
            "score" : 15,
            "finalLineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
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                "47oDynBoQifNyhG9u", 
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            "finalSubs" : [ 
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                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
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                }, 
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        }, 
        {
            "lineup" : [ 
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                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
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            "subs" : [ 
                "HcPjMYdG7FcxhRuFj", 
                "REs5NdgicB3wYwr8F", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "score" : 13,
            "finalLineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "REs5NdgicB3wYwr8F", 
                "HcPjMYdG7FcxhRuFj"
            ],
            "finalSubs" : [ 
                "gWtx6YZW5sPehiksC", 
                "QFWQLFyLvpzvfn9Nb", 
                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
                    "in" : "HcPjMYdG7FcxhRuFj",
                    "out" : "gWtx6YZW5sPehiksC"
                }, 
                {
                    "in" : "REs5NdgicB3wYwr8F",
                    "out" : "QFWQLFyLvpzvfn9Nb"
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        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
                "6xvdipvf8PNNgaB4d", 
                "A3vPEhAmhoMYA8iBm", 
                "AMDWHF8tkBLvGPwQx", 
                "MtZQjZqwptcY4MJXm", 
                "47oDynBoQifNyhG9u", 
                "QFWQLFyLvpzvfn9Nb", 
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                "HcPjMYdG7FcxhRuFj", 
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            ],
            "score" : 34,
            "finalLineup" : [ 
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            ],
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        }, 
        {
            "lineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
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            "score" : 14,
            "finalLineup" : [ 
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            ],
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                    "out" : "47oDynBoQifNyhG9u"
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        }, 
        {
            "lineup" : [ 
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                "4Csv4LDHmCku4p2d7", 
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            ],
            "score" : 19,
            "finalLineup" : [ 
                "DmwbPcTpPKoPQqJe6", 
                "4Csv4LDHmCku4p2d7", 
                "4cWjs7kjweQhTg5gq", 
                "BaRu7TonDB8iKhzdC", 
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            "finalSubs" : [ 
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                "ad7z4NnoqMsLWyhpt", 
                "ux7HCjzSpw25JYe7r"
            ],
            "autoSubs" : [ 
                {
                    "in" : "HcPjMYdG7FcxhRuFj",
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                }, 
                {
                    "in" : "REs5NdgicB3wYwr8F",
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Answer 1

所以为了简化答案，我们说一个数组a有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 } ] }

为简单起见，本例我们将检查索引2，我们可以使用聚合框架来做到这一点：

var index = 2;

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

然后输出以下内容：

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

哪个符合您的条件，但如果您这样做则非常奇怪

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什么关系？

无论如何，有关匹配null和现有文件的更多信息，请参阅 - https://docs.mongodb.com/manual/tutorial/query-for-null-fields/#equality-filter

在MongoDB中查找数组项不为null的项

1 个答案: