MongoDB join two complex collection

I got two collections

1. data

{
  _id: ObjectId('123'),
  uuid: '123abc'
  content: 'hello'
}

{
  _id: ObjectId('456'),
  uuid: '123abc'
  content: 'hi'
}

2. history

{
 _id: ObjectId('xxx'),
 uuid: '123abc'
 data: [{path: '/hello.json', objectId: '123'}, {path: '/hi.json', objectId: '456'}]
}

I want

{
  _id: ObjectId('123'),
  uuid: '123abc'
  content: 'hello'
  path: '/hello.json'
}

{
  _id: ObjectId('456'),
  uuid: '123abc'
  content: 'hi'
  path: '/hi.json'
}

Step:

1. use the uuid to find the second json
2. use the objectId of the second json data array element to locate the first json

Does anyone who knows how to write the MongoDB operations to join the two collections

the result after the second stage is finished

You can do it with Aggregation Framework:

• $lookup - To fetch data from the history collection
• $set with $first - To get the first element from the history property, since the $lookup always return an array
• $set with $filter - To create a path_element property that has the filtered history based on the document _id.
• $project - to project the data as expected output.

db.data.aggregate([
  {
    "$lookup": {
      "from": "history",
      "localField": "uuid",
      "foreignField": "uuid",
      "as": "history"
    }
  },
  {
    "$set": {
      "history": {
        "$first": "$history"
      }
    }
  },
  {
    $set: {
      path_element: {
        "$filter": {
          "input": "$history.data",
          "cond": {
            $eq: [
              {
                $toString: "$_id"
              },
              "$$this.objectId"
            ]
          }
        }
      }
    }
  },
  {
    $project: {
      _id: 1,
      uuid: 1,
      content: 1,
      path: {
        "$getField": {
          "field": "path",
          "input": {
            $first: "$path_element"
          }
        }
      }
    }
  }
])

Working example