Mongodb aggregation json format by month result - mongodb

Question

Hello I am working with the reporting api which will going to use in highcharts and I am new to mongodb.
Below is my aggregation query (suggest me modification) :
db.product_sold.aggregate({
$group: {
_id: { year: { $year: "$solddate" }, month: { $month: "$solddate" }, productid: "$productid" },
totalQty: { $sum: "$qty" }
}
})
Output:
{
"_id" : {
"year" : NumberInt(2019),
"month" : NumberInt(2),
"productid" : "11"
},
"totalQty" : 6.0
}
// ----------------------------------------------
{
"_id" : {
"year" : NumberInt(2019),
"month" : NumberInt(2),
"productid" : "14"
},
"totalQty" : 7.0
}
// ----------------------------------------------
{
"_id" : {
"year" : NumberInt(2019),
"month" : NumberInt(1),
"productid" : "13"
},
"totalQty" : 3.0
}
// ----------------------------------------------
{
"_id" : {
"year" : NumberInt(2019),
"month" : NumberInt(2),
"productid" : "10"
},
"totalQty" : 6.0
}
// ----------------------------------------------
{
"_id" : {
"year" : NumberInt(2018),
"month" : NumberInt(2),
"productid" : "12"
},
"totalQty" : 5.0
}
// ----------------------------------------------
{
"_id" : {
"year" : NumberInt(2019),
"month" : NumberInt(2),
"productid" : "15"
},
"totalQty" : 8.0
}
// ----------------------------------------------
{
"_id" : {
"year" : NumberInt(2019),
"month" : NumberInt(1),
"productid" : "11"
},
"totalQty" : 2.0
}
// ----------------------------------------------
What I want in output is something like :
status: 200,
msg: "SUCCESS"
data: [{
1:[
{
"productid": 11,
"totalQty": 3
},
{
"productid": 12,
"totalQty": 27
}
],
2:[
{
"productid": 11,
"totalQty": 64
},
{
"productid": 12,
"totalQty": 10
}
]
}]
For reference attaching the image of the collection
Is there any way to achieve it using aggregation or anything else or I will have to do it manually by code ?

Answer 1

You can append below aggreagation stages to your current pipeline:
db.product_sold.aggregate([
// your current $group stage
{
$group: {
_id: "$_id.month",
docs: { $push: { productid: "$_id.productid", totalQty: "$totalQty" } }
}
},
{
$project: {
_id: 0,
k: { $toString: "$_id" },
v: "$docs"
}
},
{
$group: {
_id: null,
data: { $push: "$$ROOT" }
}
},
{
$project: {
_id: 0,
data: { $arrayToObject: "$data" }
}
}
])
The idea here is that you can use $group with _id set to null to get all the data into single document and then use $arrayToObject to get month number as key and all the aggregates for that month as value.