Question

我有一个集合，该集合以以下格式存储文档：

# A tibble: 4 x 5
  User   FromLocation ToLocation Movement  Unit
  <chr>  <chr>        <chr>         <dbl> <dbl>
1 Newton A            A                10     2
2 Newton A            B                20     2
3 Newton B            B                20    -2
4 Newton B            B                30    -1

我想查找数量大于指定值且小于其他指定值的特定文档数组。

例如我希望项目“明信片”的库存值大于10且小于40，因此它返回给我带有库存数组的明信片的文档，该数组仅包含一个与输出匹配的元素：

/* 1 */
{
    "_id" : ObjectId("5cc1a108c5475b9e91bb7830"),
    "item" : "journal",
    "instock" : [ 
        {
            "warehouse" : "A",
            "qty" : 5.0
        }, 
        {
            "warehouse" : "C",
            "qty" : 15.0
        }
    ]
}

/* 2 */
{
    "_id" : ObjectId("5cc1a108c5475b9e91bb7831"),
    "item" : "notebook",
    "instock" : [ 
        {
            "warehouse" : "C",
            "qty" : 5.0
        }
    ]
}

/* 3 */
{
    "_id" : ObjectId("5cc1a108c5475b9e91bb7832"),
    "item" : "paper",
    "instock" : [ 
        {
            "warehouse" : "A",
            "qty" : 60.0
        }, 
        {
            "warehouse" : "B",
            "qty" : 15.0
        }
    ]
}

/* 4 */
{
    "_id" : ObjectId("5cc1a108c5475b9e91bb7833"),
    "item" : "planner",
    "instock" : [ 
        {
            "warehouse" : "A",
            "qty" : 40.0
        }, 
        {
            "warehouse" : "B",
            "qty" : 5.0
        }
    ]
}

/* 5 */
{
    "_id" : ObjectId("5cc1a108c5475b9e91bb7834"),
    "item" : "postcard",
    "instock" : [ 
        {
            "warehouse" : "B",
            "qty" : 15.0
        }, 
        {
            "warehouse" : "C",
            "qty" : 35.0
        },
        {
            "warehouse" : "M",
            "qty" : 50.0
        }
    ]
}

/* 6 */
{
    "_id" : ObjectId("5cc1a16ea794ebd5fc278172"),
    "item" : "dig",
    "instock" : [ 
        {
            "warehouse" : "A",
            "qty" : 5.0
        }
    ]
}

Answer 1

您可以使用$match进行文档级过滤，并使用$filter将条件应用于数组：

db.collection.aggregate([
    {
        $match: { item: "postcard" }
    },
    {
        $addFields: {
            instock: {
                $filter: {
                    input: "$instock",
                    cond: {
                        $and: [
                            { $gt: [ "$$this.qty", 10 ] },
                            { $lt: [ "$$this.qty", 30 ] }
                        ]
                    }
                }
            }
        }
    }
])

Mongo Playground

如何在mongoDb文档中查找特定数组元素并进行查询和带范围过滤？

1 个答案: