Question

我们会在find（）命令中使用什么查询文档来返回video.movieDetails集合中所有获得或被提名以获得最佳图片的电影？您可以假设只有在电影获胜或被提名时，奖项才会出现在“奥斯卡”阵列中。

"awards" : {
        "oscars" : [
            {"award": "bestAnimatedFeature", "result": "won"},
            {"award": "bestMusic", "result": "won"},
            {"award": "bestPicture", "result": "nominated"},
            {"award": "bestSoundEditing", "result": "nominated"},
            {"award": "bestScreenplay", "result": "nominated"}
        ],
        "wins" : 56,
        "nominations" : 86,
        "text" : "Won 2 Oscars. Another 56 wins and 86 nominations."
    }

Answer 1

您的意思是这个查询吗？

db.movie.find({"awards.oscars.award":"bestPicture"})

输入：

{
    "_id" : ObjectId("569a7f590586bcb40f7d2532"),
    "awards" : {
        "oscars" : [ 
            {
                "award" : "bestAnimatedFeature",
                "result" : "won"
            }, 
            {
                "award" : "bestMusic",
                "result" : "won"
            }, 
            {
                "award" : "bestPicture",
                "result" : "nominated"
            }, 
            {
                "award" : "bestSoundEditing",
                "result" : "nominated"
            }, 
            {
                "award" : "bestScreenplay",
                "result" : "nominated"
            }
        ],
        "wins" : 56,
        "nominations" : 86,
        "text" : "Won 2 Oscars. Another 56 wins and 86 nominations."
    }
}

{
    "_id" : ObjectId("569a7fc60586bcb40f7d2533"),
    "awards" : {
        "oscars" : [ 
            {
                "award" : "bestScreenplay",
                "result" : "nominated"
            }
        ],
        "wins" : 12,
        "nominations" : 15,
        "text" : "Won 1 Oscars. Another 12 wins and 15 nominations."
    }
}

结果

{
    "_id" : ObjectId("569a7f590586bcb40f7d2532"),
    "awards" : {
        "oscars" : [ 
            {
                "award" : "bestAnimatedFeature",
                "result" : "won"
            }, 
            {
                "award" : "bestMusic",
                "result" : "won"
            }, 
            {
                "award" : "bestPicture",
                "result" : "nominated"
            }, 
            {
                "award" : "bestSoundEditing",
                "result" : "nominated"
            }, 
            {
                "award" : "bestScreenplay",
                "result" : "nominated"
            }
        ],
        "wins" : 56.0000000000000000,
        "nominations" : 86.0000000000000000,
        "text" : "Won 2 Oscars. Another 56 wins and 86 nominations."
    }
}

Answer 2

如果我们可以假设bestPicture位于第2位，那么我们可以执行以下

{
    "$or": [{
        "awards.oscars.2.result": "won"
    },
    {
        "awards.oscars.2.result": "nominated"
    }]
})

如果我们想确保胜利和提名确实存在，那么我们可能应该运行

{
    "$and": [{
        "$or": [{
            "awards.wins": {
                "$gt": 0
            }
        },
        {
            "awards.nominations": {
                "$gt": 0
            }
        }]
    },
    {
        "$or": [{
            "awards.oscars.2.result": "won"
        },
        {
            "awards.oscars.2.result": "nominated"
        }]
    }]
}

或者我们可以使用elemMatch

{
    "awards.oscars": {
        "$elemMatch": {
            "$or": [{
                "award": "bestPicture",
                "result": "won"
            },
            {
                "award": "bestPicture",
                "result": "nominated"
            }]
        }
    }
}

如何在集合中的数组中存在或不存在属性？

2 个答案: