I tried to iterate array inside object key value using mongodb.but its not working.how to achieve it.
Database code
0
Add a comment
|
2 Answers
You can use below aggregation
db.product.aggregate([
{ "$lookup": {
"from": "category",
"localField": "id",
"foreignField": "_id",
"as": "ordersetails"
}},
{ "$project": {
"product_name": 1,
"product_image": { "$arrayElemAt": ["$product_image", 0] },
"ordersetails": { "$arrayElemAt": ["$ordersetails.name", 0] }
}}
]).toArray()
3 Comments
Rishabh Garg
It will not work if you have more than one records in ordersdetails.
Ashh
@RishabhGarg Please check the
localField and the foreignField. It is targeting to _id of the other collection which means the record is unique. Hope you will get it.Rishabh Garg
@Fanpark Yes, True. Missed the _id.
If you have multiple object in orderdetails array then you can use the following query :
db.product.aggregate([
{
$lookup: {
from: "category",
localField: "category_id",
foreignField: "id",
as: "ordersetails"
}
},
{
$project: {
product_name: 1,
product_image: { $arrayElemAt: ["$image", 0] },
ordersetails: 1
}
},
{
$unwind: "ordersetails"
},
{
$project: {
product_name: 1,
product_image: 1,
ordersetails: "$ordersetails.name"}
}
},
]).toArray();