I am working on an app that uses MongoDB (I use Mongoose) as its database.
I have a question, suppose I have this kind of schema:
[{
"user_id":"2328292073"
"username":"Bob",
"subscriptions":[
{
"id":"38271281,
"payments":[
{
"id":"00001",
"amount":"1900"
},
{
"id":"00002",
"amount":"2000"
},
{
"id":"00003",
"amount":"3000"
}
]
}
]
}]In my case I want to get the payments array for subscription with id = '38271281' of user with id '2328292073', but I just want to retrieve the payment array, nothing else
My query is the following:
Mongoose.findOne({
"user_id": "2328292073",
"subscriptions.id": "38271281"
},
{
"subscriptions.payments": 1
})But I get the entire document of subscriptions. How can i get the payment array only?
you can try using unwind if you want filteration from db only.
Mongoose.aggregate([
{
'$match': {
'user_id': '2328292093'
}
}, {
'$unwind': {
'path': '$subscriptions'
}
}, {
'$match': {
'subscriptions.id': '38271281'
}
}
])
if you will have multiple documents having same subscription id then you have to group it .
You can try aggregation operators in projection in find method or also use aggregation method,
$reduce to iterate loop of subscriptions and check the condition if id matched then return payment arraydb.collection.find({
"user_id": "2328292073",
"subscriptions.id": "38271281"
},
{
payments: {
$reduce: {
input: "$subscriptions",
initialValue: [],
in: {
$cond: [
{ $eq: ["$$this.id", "38271281"] },
"$$this.payments",
"$$value"
]
}
}
}
})