Mongodb output field with multiple $cond - mongodb

Question

Here's an example of documents I use :
{
"_id" : ObjectId("554a1f5fe36a768b362ea5c0"),
"store_state" : 1,
"services" : [
{
"id" : "XXX",
"state" : 1,
"active": true
},
{
"id" : "YYY",
"state" : 1,
"active": true
},
...
]
}
I want to output a new field with "Y" if the id is "XXX" and active is true and "N" in any other cases. The service element with "XXX" as id is not present on every documents (output "N" in this case).
Here's my query for the moment :
db.stores.aggregate({
$match : {"store_state":1}
},
{ $project : {
"XXX_active": {
$cond: [ {
$and:[
{$eq:["services.$id","XXX"]},
{$eq:["services.$active",true]}
]},"Y","N"
] }
}
}).pretty()
But it always output "N" for "XXX_active" field.
The expected output I need is :
{
"_id" : ObjectId("554a1f5de36a768b362e7e6f"),
"XXX_active" : "Y"
},
{
"_id" : ObjectId("554a1f5ee36a768b362e9d25"),
"XXX_active" : "N"
},
{
"_id" : ObjectId("554a1f5de36a768b362e73a5"),
"XXX_active" : "Y"
}
Other example of possible result :
{
"_id" : ObjectId("554a1f5de36a768b362e7e6f"),
"XXX_active" : "Y",
"YYY_active" : "N"
},
{
"_id" : ObjectId("554a1f5ee36a768b362e9d25"),
"XXX_active" : "N",
"YYY_active" : "N"
},
{
"_id" : ObjectId("554a1f5de36a768b362e73a5"),
"XXX_active" : "Y",
"YYY_active" : "Y"
}
Only one XXX_active per object and no duplicates objects but I need all objects with an XXX_active even if the services id element "XXX" is not present. Could someone help please?

Answer 1

First $unwind services array and then used $cond as below :
db.stores.aggregate({
"$match": {
"store_state": 1
}
}, {
"$unwind": "$services"
}, {
"$project": {
"XXX_active": {
"$cond": [{
"$and": [{
"$eq": ["$services.id", "XXX"]
}, {
"$eq": ["$services.active", true]
}]
}, "Y", "N"]
}
}
},{"$group":{"_id":"$_id","XXX_active":{"$first":"$XXX_active"}}}) //group by id

Answer 2

The following aggregation pipeline will give the desired result. You would need to first apply the $unwind operator on the services array field first as your initial aggregation pipeline step. This will deconstruct the services array field from the input documents to output a document for each element. Each output document replaces the array with an element value.
db.stores.aggregate([
{
"$match" : {"store_state": 1}
},
{
"$unwind": "$services"
},
{
"$project": {
"store_state" : 1,
"services": 1,
"XXX_active": {
"$cond": [
{
"$and": [
{"$eq":["$services.id", "XXX"]},
{"$eq":["$services.active",true]}
]
},"Y","N"
]
}
}
},
{
"$match": {
"services.id": "XXX"
}
},
{
"$group": {
"_id": {
"_id": "$_id",
"store_state": "$store_state",
"XXX_active": "$XXX_active"
},
"services": {
"$push": "$services"
}
}
},
{
"$project": {
"_id": "$_id._id",
"store_state" : "$_id.store_state",
"services": 1,
"XXX_active": "$_id.XXX_active"
}
}
])