MongoDb查询以在嵌套数组中查找特定对象

Question

i have an array of object player_of_day inwhich there is again array of user-Ids ie nominate_by I want to find an object having maximum count. Something like- an object from player_of_day whose count is maximum

"player_of_day" : [
        {
            "nominate_by" : [
                ObjectId("58994bca4187b412aec50c94"),
                ObjectId("58994a124187b412aec50c91"),
                ObjectId("589955d54187b412aec50c99")
            ],
            "nominate_to" : ObjectId("58994b374187b412aec50c93"),
            "count" : 3
        },
        {
            "nominate_by" : [
                ObjectId("58994c254187b412aec50c95"),
                ObjectId("58994ad04187b412aec50c92")
            ],
            "nominate_to" : ObjectId("58994a124187b412aec50c91"),
            "count" : 2
        },
        {
            "nominate_by" : [
                ObjectId("58994b374187b412aec50c93")
            ],
            "nominate_to" : ObjectId("58994c254187b412aec50c95"),
            "count" : 1
        }
    ],

Answer 1

你可以使用$ unwind

db.match.aggregate([{"$unwind":"$player_of_day"},{"$sort":{'player_of_day.count':-1}},{"$limit":1}]);