How to group orders by data range in MongoDB? - mongodb

Question

Suppose I have a collection like this:
[
{
"_id": ObjectId("5e3dd3d57f8bc30a7513e843"),
"deleted": true,
"date": "01/01/2020"
"total": 3
},
{
"_id": ObjectId("5e3dd3e97f8bc30a7513e99b"),
"date": "02/01/2020",
"deleted": false,
"total": 11
},
{
"_id": ObjectId("5e3dd3e97f8bc30a75137635"),
"date": "15/02/2020",
"deleted": false,
"total": 5
},
{
"_id": ObjectId("5e3dd3e97f8bc30a75131725"),
"date": "18/02/2020",
"deleted": false,
"total": 7
},
{
"_id": ObjectId("5e3dd3e97f8bc30a75131725"),
"date": "03/03/2020",
"deleted": false,
"total": 9
}
]
I need to merge these orders by a range to receive something like this:
{
"january": [order1, order2],
"february": [order3, order4],
"march": [order5]
}
of course I don't need the words "january, february" etc specifically, just something that let me group by data ranges. Something like this:
db.sales.aggregate( [
{ $group: { date: { "$gte": new Date(req.query.minDate), "$lte": new Date(req.query.maxDate) }, mergedOrders: { ?? } } }
])
which is not near a valid group aggregate call.
So, how do I group orders by data range? (I need to get, for each data range, the entire array of orders in that data range, as they are, without excluding fields)

Answer 1

You can try this :
db.sales.aggregate([
{ $match: { date: { "$gte": new Date(req.query.minDate), "$lte": new Date(req.query.maxDate) } } },
{
$group: {
_id: {
$month: {
$dateFromString: {
dateString: '$date',
format: "%d/%m/%Y"
}
}
}, mergedOrders: { $push: '$$ROOT' }
}
}, {
$addFields: {
_id: {
$let: {
vars: {
monthsInString: ['', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'July', 'Aug', 'Sept', 'Oct', 'Nov', 'Dec']
},
in: {
$arrayElemAt: ['$$monthsInString', '$_id']
}
}
}
}
}])
Test : MongoDB-Playground

Answer 2

You can use $group operator to group data based on a particular value in field. Then you may use push operator to have array of those values.
db.sales.aggregate([
$match: {
date: { "$gte": new Date(req.query.minDate), "$lte": new Date(req.query.maxDate) }
},
$group : {
_id: "$date",
orders: {
$push: {
deleted: "$deleted",
total: "$total"
}
}
},
$project: {
_id: 1,
orders: 1
}
)];