Query MongoDB for nested Arrays - mongodb

Question

Need help for formatting query to find/get values using search parameters with nested Array.
I have an collection as follows
[
{
"_id": "5b3ad55f66479332a0482961",
"timestamp": "2018-06-17T00:30:00.000Z",
"deviceid": "123456",
"values": [
{
"minval": 1,
"minvalues": [
{
"secval": 51,
"secvalues": {
"alt": "300",
"mcc": "404",
"mnc": "46",
"priority": 1
}
},
{
"secval": 52,
"secvalues": {
"alt": "300",
"mcc": "404",
"mnc": "46",
"priority": 1
}
},
{
"secval": 56,
"secvalues": {
"alt": "300",
"mcc": "404",
"mnc": "46",
"priority": 0
}
}
]
}
]
}
]
need the out as follows with search properties as "values.minvalues.secvalues.priority"
[
{
"_id": "5b3ad55f66479332a0482961",
"timestamp": "2018-06-17T00:30:00.000Z",
"deviceid": "123456",
"values": [
{
"minval": 1,
"minvalues": [
{
"secval": 56,
"secvalues": {
"alt": "300",
"mcc": "404",
"mnc": "46",
"priority": 0
}
}
]
}
]
}
]
I tried the following query but with out success
dbRetval.db('ls_gpsdatabase').collection('gpsevent').aggregate([
{ "$match": { "deviceid": { "$in": idList}}},
{ "$sort": { "_id": -1} },
{"$unwind":"$values.minvalues.secvalues"},
//{"$project":{"deviceid":1,"values.minvalues.secvalues.lat":1,"values.minvalues.secvalues.min":1}} ,
{ "$match": { "values.minvalues.secvalues.priority": { "$eq": 1}}},
{ "$group": { "_id": "$deviceid" , "doc": { "$push": "$values.minvalues.secvalues" }}} ]).toArray();
If any can help that would be great full.

Answer 1

You can use $addFields to replace existing field. Since you have two levels of nested arrays you can use $map for outer and $filter for inner to check your condition:
db.col.aggregate([
{
$match: {
"_id": "5b3ad55f66479332a0482961",
"timestamp": "2018-06-17T00:30:00.000Z"
}
},
{
$addFields: {
values: {
$map: {
input: "$values",
as: "value",
in: {
minval: "$$value.minval",
minvalues: {
$filter: {
input: "$$value.minvalues",
as: "minvalue",
cond: {
$eq: [ "$$minvalue.secvalues.priority", 0 ]
}
}
}
}
}
}
}
}
])