mongodb - mongodb $match 中的多个条件

Question

我有一个集合 AccountSupport。我有一系列支持属性。我想过滤父属性和数组属性的记录

db = {
  "AccountSupport": [
    {
    "_id" : ObjectId("5e9c6170b38c373530c5b00a"),
    "accountName" : "domestic",
    "supports" : [ 
        {
            "subject" : "Traverse",
            "desc" : "Travers support consolidation",
        }, 
        {
            "subject" : "Non Traverse",
            "desc" : "Non Travers support consolidation",
        },
        {
            "subject" : "Domestic Traverse",
            "desc" : "Domestic Travers support consolidation",
        }       
    ],

  }

我想过滤 accountName 和 support.subject。

以下是我的查询

db.AccountSupport.aggregate([
  {
    "$match": {
      "$and": [
        {
          "supports.subject": "Traverse"
        },
        {
          "accountName": "domestic"
        }
      ]
    }
  },
  {
    "$unwind": "$supports"
  },
  {
    "$project": {
      "SupportName": "$supports.subject",
      "desc": "$supports.desc"
    }
  }
])

上面的查询返回特定 accountName 的所有支持，而我只想要匹配主题的单个对象。以上是最简单的方法吗？

MongoPlayGround

MongoPlayGround for my query

Answer 1

进行了一些实验，但试试这个:

db.AccountSupport.aggregate([
  {
    $match: {
      "accountName": "domestic",
      "supports.subject": "Traverse"
    }
  },
  {
    $project: {
      accountName: "$accountName",
      subject: {
        $filter: {
          input: "$supports",
          as: "supports",
          cond: {
            $eq: [
              "$$supports.subject",
              "Traverse"
            ]
          }
        }
      },
      _id: 0
    }
  }
])

返回:

[
  {
    "accountName": "domestic",
    "subject": [
      {
        "desc": "Travers support consolidation",
        "subject": "Traverse"
      }
    ]
  }
]