RESTHeart filtering and sorting by sub documents property - mongodb

Question

I m working with mongodb and restheart.
In my nosql db i have a unique document with this structure:
{
"_id": "docID",
"users": [
{
"userID": "12",
"elements": [
{
"elementID": "1492446877599",
"events": [
{
"id": 1,
"date": 356
},
{
"id": 2,
"date": 123
}
]
}
]
},
{
"userID": "11",
"elements": [
{
"elementID": "14924",
"events": [
{
"id": 1,
"date": 123
},
{
"id": 2,
"date": 356
}
]
},
{
"elementID": "14925",
"events": [
{
"id": 1,
"date": 12
},
{
"id": 2,
"date": 36
}
]
}
]
}
i need to filter the user with userID = 11 and i need to order his events by ascending date.
i was trying with:
http://myhost:port/myCollection?keys={"users":{"$elemMatch":{"userID":"11"}}}&sort_by={"users.elements.events.date":-1}
but it doesn t work.

Answer 1

db.v.aggregate([
{ $unwind : '$users'},
{ $match : { 'users.userID' : '11' }} ,
{ $unwind : '$users.elements'},
{ $unwind : '$users.elements.events'},
{ $sort : {'users.elements.events.date': 1}},
{ $group : {
_id : '$_id',
elementID : { $first : '$users.elements.elementID' },
userID : { $first : '$users.userID' },
events : { $push : '$users.elements.events'}
}
},
{ $project : {
_id : 1,
userID : 1,
'elements.elementID' : '$elementID',
'elements.events' : '$events'
}
}
]);
This will give you following :
{
"_id" : ObjectId("5911ba55f0d9c285c561ea33"),
"userID" : "11",
"elements" : {
"elementID" : "14924",
"events" : [
{
"id" : 1,
"date" : 123
},
{
"id" : 2,
"date" : 356
}
]
}
}