如何根据条件在mongodb中查询嵌入式对象数组答案

【问题标题】：How to query embedded array of objects based on conditions in mongodb如何根据条件在mongodb中查询嵌入式对象数组
【发布时间】：2023-01-14 00:11:41
【问题描述】：

我有一个嵌入在文档中的对象数组，并且集合中有多个这样的文档。如何查询具有以下条件的那些嵌入式对象数组（基于我下面的文档）。

首先获取"status"为"active"的对象（状态不会出现在所有对象中，只会出现在少数对象中）
然后得到上面满足的对象的"parent_user_id"，和剩下的对象"parent_user_id"匹配，得到那些对象

必须设置上述条件的结果，而不是输出中对象的原始数组（即："users"），而不是所有存在的对象。因此，如果您查看结果，我预计用户数组中缺少 3 个元素，因为这些元素不满足上述条件。我收集的文件（将有多个文件）

{
    "_id" : ObjectId("63a8808652f40e1d48a3d1d7"),
    "name" : "A",
    "description" : null,
    "users" : [
        {
            "id" : "63a8808c52f40e1d48a3d1da",
            "owner" : "John Doe",
            "purchase_date" : "2022-12-25,
            "status" : "active",
            "parent_user_id" : "63a8808c52f40e1d48a3d1da",
            "recent_items": ["tomato",onion]
        },
        {
            "id" : "63a880a552f40e1d48a3d1dc",
            "owner" : "John Doe 1",
            "purchase_date" : "2022-12-25,
            "parent_user_id" : "63a8808c52f40e1d48a3d1da",
            "recent_items": ["onion"]
        },
        {
            "id" : "63a880f752f40e1d48assddd"
            "owner" : "John Doe 2",
            "purchase_date" : "2022-12-25,
            "parent_user_id" : "63a8808c52f40e1d48a3d1da",
        },
        {
            "id" : "63a880f752f40e1d48a3d207"
            "owner" : "John Doe 11",
            "dt" : "2022-12-25,
            "status" : "inactive",
            "parent_user_id" : "63a880f752f40e1d48a3d207",
        },
        {
            "id" : "63a880f752f40e1d48agfmmb"
            "owner" : "John Doe 112",
            "dt" : "2022-12-25,
            "status" : "active",
            "parent_user_id" : "63a880f752f40e1d48agfmmb",
            "recent_items": ["tomato"]
        }
        {
            "id" : "63a880f752f40e1d48agggg"
            "owner" : "John SS",
            "dt" : "2022-12-25,
            "status" : "inactive",
            "parent_user_id" : "63a880f752f40e1d48agggg",
        }
        {
            "id" : "63a880f752f40e1d487777"
            "owner" : "John SS",
            "dt" : "2022-12-25,
            "parent_user_id" : "63a880f752f40e1d48agggg",
        }
    ]
}

结果很期待

{
  "_id" : ObjectId("63a8808652f40e1d48a3d1d7"),
  "name" : "A",
  "description" : null,
        "users" : [
            {
                "id" : "63a8808c52f40e1d48a3d1da",
                "owner" : "John Doe",
                "purchase_date" : "2022-12-25,
                "status" : "active",
                "parent_user_id" : "63a8808c52f40e1d48a3d1da",
                "recent_items": ["tomato",onion]
            },
            {
                "id" : "63a880a552f40e1d48a3d1dc",
                "owner" : "John Doe 1",
                "purchase_date" : "2022-12-25,
                "parent_user_id" : "63a8808c52f40e1d48a3d1da",
            },
            {
                "id" : "63a880f752f40e1d48assddd"
                "owner" : "John Doe 2",
                "purchase_date" : "2022-12-25,
                "parent_user_id" : "63a8808c52f40e1d48a3d1da",
            },
            {
                "id" : "63a880f752f40e1d48agfmmb"
                "owner" : "John Doe 112",
                "dt" : "2022-12-25,
                "status" : "active",
                "parent_user_id" : "63a880f752f40e1d48agfmmb",
                "recent_items": ["tomato"]
            }
        ]
    }

【问题讨论】：

标签： mongodb aggregation-framework aggregate

【解决方案1】：

我会使用一些 $filter 阶段如下：

db.collection.aggregate([
  {
    $addFields: {
      users_matched: {
        $filter: {
          input: "$users",
          as: "user",
          cond: {
            $eq: [
              "active",
              "$$user.status"
            ],
            
          },
          
        },
        
      },
      
    },
    
  },
  {
    $set: {
      users: {
        $filter: {
          input: "$users",
          as: "user",
          cond: {
            $in: [
              "$$user.parent_user_id",
              "$users_matched.id"
            ],
            
          },
          
        },
        
      },
      
    },
    
  },
  {
    $unset: "users_matched"
  }
])

可以自己去mongoplayground查查https://mongoplayground.net/p/SrpsWb4v21x

【讨论】：

上述解决方案有效，谢谢。但是还有一个问题。