如何使用聚合从 mongodb 中的两个 collections 查询？

Question

I have the two following collections in my mongoDB:

PRODUCTS:

[
    {
        "_id": "5ebb0984e95e3e9e35aab3bf",
        "name": "Product 1",
        "brand": "ABC",
        "code": "7891910000190",
        "description": "Lorem Ipsum"
    },
    {
        "_id": "5ebdb9f3d943ae000a4a9714",
        "name": "Product 2",
        "brand": "DEF",
        "code": "7891910000190",
        "description": "Lorem Ipsum"
    }
]

STOCK GOODS:

[
    {
        "_id": "5ed0586b7f2cfe02387d0706",
        "companyId": "5ed0491bf9a892a5fd9b4d9b",
        "branchId": "5ed049a8f9a892a5fd9b4d9e",
        "inventoryId": "5ed04d01e9e43cee79734b95",
        "productId": "5ebb0984e95e3e9e35aab3bf"
    },
    {
        "_id": "5ed058da75e4e01013f5779d",
        "companyId": "5ed0491bf9a892a5fd9b4d9b",
        "branchId": "5ed049a8f9a892a5fd9b4d9e",
        "inventoryId": "5ed04cede9e43cee79734b93",
        "productId": "5ebb0984e95e3e9e35aab3bf"
    },
    {
        "_id": "5ed059483da3bafccb34cec3",
        "companyId": "5ed0491bf9a892a5fd9b4d9b",
        "branchId": "5ed049a8f9a892a5fd9b4d9e",
        "inventoryId": "5ed04d01e9e43cee79734b95",
        "productId": "5ebb0984e95e3e9e35aab3bf"
    }
]

I want to get the follow result:

[
    {
        "_id": "5ed0586b7f2cfe02387d0706",
        "data": {
            "_id": "5ebb0984e95e3e9e35aab3bf",
            "brand": "ABC",
            "code": "7891910000190",
            "description": "Lorem Ipsum",
            "name": "Product 1",
        }
    },
    {
        "_id": "5ed059483da3bafccb34cec3",
        "data": {
            "_id": "5ebb0984e95e3e9e35aab3bf",
            "brand": "ABC",
            "code": "7891910000190",
            "description": "Lorem Ipsum",
            "name": "Product 1",
        }
    }
]

My NodeJS and MongoDB aggregate look like this:

const mongoose = require("mongoose");
const StockGoods = mongoose.model("StockGoods");
ObjectId = require("mongodb").ObjectID;

exports.getProducts = async (companyId, branchId, inventoryId) => {
  const response = await StockGoods.aggregate([
    {
      $match: {
        companyId: new ObjectId("5ed0491bf9a892a5fd9b4d9b"), // new ObjectId(companyId)
        inventoryId: new ObjectId("5ed04d01e9e43cee79734b95"), // new ObjectId(inventoryId)
        branchId: new ObjectId("5ed049a8f9a892a5fd9b4d9e"), // new ObjectId(branchId)
      },
    },
    {
      $lookup: {
        from: "products",
        localField: "productId",
        foreignField: "_id",
        as: "inventory_docs",
      },
    },
    {
      $project: {
        data: "$inventory_docs",
      },
    },
    { $unwind: "$data" },
  ]);
  return response;
};

This is the same database and the aggregate function described above, you can check this: https://mongoplayground.net/p/FRgAIfO2bwh .

But, this function aggregate does not working when I use nodejs. My API returns nothing (empty array).

Whats wrong?

Answer 1

Issue here is the way you have stored data in collection.... StockGoods collection has companyId, inventoryId and branchIdas a string but aggregation is looking for ObjectId aee below match criteria:

 $match: {
    companyId: new ObjectId("5ed0491bf9a892a5fd9b4d9b"), // new ObjectId(companyId)
    inventoryId: new ObjectId("5ed04d01e9e43cee79734b95"), // new 
    ObjectId(inventoryId)
    branchId: new ObjectId("5ed049a8f9a892a5fd9b4d9e"), // new ObjectId(branchId)
  },

Based on the data you store in DB either you need to update match with string.

So below Aggregation will work for you..

[
 {
  "$match": {
     "companyId": "5ed0491bf9a892a5fd9b4d9b",
     "inventoryId": "5ed04d01e9e43cee79734b95",
     "branchId": "5ed049a8f9a892a5fd9b4d9e"
  }
  },
 {
  "$lookup": {
     "from": "products",
     "localField": "productId",
     "foreignField": "_id",
     "as": "inventory_docs"
  }
  },
 {
  "$project": {
     "data": "$inventory_docs"
  }
 },
{
  "$unwind": "$data"
}

]

This works you can test in Compass Aggregator tab

Answer 2

[RESOLVED]

The problem was in the scheme:

companyId: {
    type: String,
    required: true,
},

The correct is:

companyId: {
    type: Schema.Types.ObjectId,
    required: true,
},