如何从文档中的双嵌套数组中选择特定对象

Question

我有以下文件：

{
"month": 2,
"year": 2019,
"categories": [
    {
        "title": "Income",
        "budget": 5000,
        "amount": 2000,
        "subcategories": [
            {
                "title": "Paychecks",
                "budget": 4000,
                "amount": 1000,
                "transactions": [
                    {
                        "day": 3,
                        "amount": 600,
                        "vendor": "Microsoft",
                        "memo": "Paycheck 1"
                    },
                    {
                        "day": 10,
                        "amount": 400,
                        "vendor": "Google",
                        "memo": "Paycheck 2"
                    }
                ]
            },
            {
                "title": "Other",
                "budget": 1000,
                "amount": 1000,
                "transactions": [
                    {
                        "day": 7,
                        "amount": 600,
                        "vendor": "Mom",
                        "memo": "Gift for Baby"
                    },
                    {
                        "day": 19,
                        "amount": 400,
                        "vendor": "Amy",
                        "memo": "Gift for Julie"
                    }
                ]
            }
        ]
    },
    {
        "title": "Housing",
        "budget": 3000,
        "amount": 3000,
        "subcategories": [
            {
                "title": "Rent",
                "budget": 2000,
                "amount": 2000,
                "transactions": [
                    {
                        "day": 1,
                        "amount": 2000,
                        "vendor": "Homes4Rent",
                        "memo": "Rent"
                    }
                ]
            },
            {
                "title": "Electric",
                "budget": 1000,
                "amount": 1000,
                "transactions": [
                    {
                        "day": 14,
                        "amount": 1000,
                        "vendor": "Tampa Electric",
                        "memo": "Electric"
                    }
                ]
            }
        ]
    }
]}

我想从一个非常特定的类别中删除一个非常特定的子类别。例如，我想从该文档的“房屋”类别中删除“出租”子类别。

我尝试了各种查询，但是无论它们在哪个类别中，它们都只会删除名为“ Rent”的所有子类别。我正在学习聚合框架，并且已经成功地将其用于其他查询，但是我对这个框架并不太幸运。

这是到目前为止我能提出的最好的查询：

db.collection.update(
  {
    "year":2019,
    "month":2,
    "categories.title":"Housing",
    "categories.subcategories.title":"Rent"
  },
  {
    $pull:{
      "categories.$.subcategories":"Rent"
    }
  }
)

不幸的是，这导致：

WriteResult({"nMatched":1, "nUpserted":0, "nModified":0})

如果我需要进一步澄清任何内容，请告诉我。非常感谢。