mongodb find from array and then from object id by refrence - mongodb

Question

I want to seach order list with product division id. means i can provide division id and get order list of that perticular division.
I'm trying this query, but it return 0 elements
db.getCollection('orders').find({$or:
[{'orderlist':{"$elemMatch":{'product_id.division_id':ObjectId("5f5b1511a859865ac9b0efe5")}}}]
})
My Order Schema
const orderSchema = new mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
orderlist: [{
product_id: { type: mongoose.Schema.Types.ObjectId, ref: 'Product', required: [true, "Product Id is Required"] },
quantity: { type: Number, required: [true, "Product Quantity is Required"] },
packing_type: { type: String, default: null }
}]
});
My Product Schema
const productSchema = new mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
division_id: { type: mongoose.Schema.Types.ObjectId, ref: 'Division', required: [true, "Product Division Id is Required"] },
name: { type: String, required: [true, "Product Name is Required"] },
price: { type: Number, required: [true, "Product Price is Required"] },
description: { type: String, required: [true, "Product Description is Required"] },
technical_detail: { type: String, default: null },
packing: { type: String, default: null },
packing_type: { type: String, default: null }
});```

Answer 1

To filter query calls with a ref schema first of all you need to lookup it from the server. In your case, it is a mongoose object id not an object of elements.
To merge schemas I recommend using aggregation.$lookup(aggregation)
db.getCollection('orders').aggregate([
{
$lookup: {
from: 'product',
localField: 'orderlist.product_id',
foreignField: '_id',
as: 'products',
},
},
])