Mongo forEach Query - json

Question

I have the JSON that you can see below and I want to sum the values of the two objects, but when I make an aggregation it returns me 0.Here you can see the query that I use; really the first line I only use it to be sure that the path works, and it does. On the other hand,when I use this path in the aggregation query it gives me the "ID" and the "COUNT" with right values,but the "SUM" is always 0 when it must be 3600.Any idea?
db.getCollection('TEST').find({"prices.year.months.day.csv.price.valPrice":1800})
db.TEST.aggregate([
{ $match: {"location.cp":"20830"}},
{$group:{_id:"20830",total:{$sum:"$prices.year.months.day.csv.price.valPrice"}, count: { $sum: 1 }
}}])
And this is the JSON:
{
"_id" : "20830:cas:S:3639",
"lodgtype" : "Casa",
"lodg" : "Motrico: country holiday home - San sebastian",
"webid" : "6107939",
"location" : {
"thcod" : "20",
"cp" : "20830",
"th" : "Gipuzkoa",
"geometry" : {
"type" : "Point",
"coordinates" : [
43.31706238,
-2.40293598
]
}
},
"prices" : {
"year" : [
{
"valYear" : "2018",
"months" : [
{
"valMonth" : "02",
"day" : [
{
"valDay" : "13",
"csv" : [
{
"valCsv" : "20180205210908_223",
"price" : [
{
"valPrice" : 1800.0
}
]
}
]
}
]
}
]
}
]
},
"reg" : {
"created" : "20180213",
"updated" : "20180213",
"viewed" : "20180213"
}
},{
"_id" : "TEST20830:cas:S:3639",
"lodgtype" : "Casa",
"lodg" : "TESTMotrico: country holiday home - San sebastian",
"webid" : "6107930",
"location" : {
"thcod" : "20",
"cp" : "20830",
"th" : "Gipuzkoa",
"geometry" : {
"type" : "Point",
"coordinates" : [
43.31706238,
-2.40293598
]
}
},
"prices" : {
"year" : [
{
"valYear" : "2018",
"months" : [
{
"valMonth" : "02",
"day" : [
{
"valDay" : "13",
"csv" : [
{
"valCsv" : "20180205210908_223",
"price" : [
{
"valPrice" : 1800.0
}
]
}
]
}
]
}
]
}
]
},
"reg" : {
"created" : "20180213",
"updated" : "20180213",
"viewed" : "20180213"
}
}

Answer 1

Since you've deeply nested array you've to unwind to flatten to a document structure. To count the number of matches you've to use extra group after $match with $push with $$ROOT to keep the matching data.
db.TEST.aggregate([
{"$match":{"location.cp":"20830"}},
{"$group":{
"_id":"20830",
"data":{"$push":"$$ROOT"},
"count":{"$sum":1}
}},
{"$unwind":"$data.prices.year"},
{"$unwind":"$data.prices.year"},
{"$unwind":"$data.prices.year.months"},
{"$unwind":"$data.prices.year.months.day"},
{"$unwind":"$data.prices.year.months.day.csv"},
{"$unwind":"$data.prices.year.months.day.csv.price"},
{"$group":{
"_id":"20830",
"total":{"$sum":"$prices.year.months.day.csv.price.valPrice"},
"count":{"$first":"$count"}
}}
])