Need help on mongo aggregation query - mongodb

Question

Below is the sample data:
[{
"outdoor": {
"location": {
"type": "Point",
"coordinates": [
-92.41151,
35.11683
]
}
},
"geoHash": "dr72jwgnbbst", "status":"Active","customerId":"8047380094","locationId":"A0"
},
{
"outdoor": {
"location": {
"type": "Point",
"coordinates": [
-89.58342,
36.859161
]
}
},
"geoHash": "dn6qtkr5xk8m", "status":"Pending","customerId":"8047380094","locationId":"A1"
},
{
"outdoor": {
"location": {
"type": "Point",
"coordinates": [
-86.038762,
36.519016
]
}
},
"geoHash": "dn6zf0h6xtcp", "status":"Active","customerId":"8047380094","locationId":"A2"
},
{
"outdoor": {
"location": {
"type": "Point",
"coordinates": [
-98.3081936,
26.2143207
]
}
},
"geoHash": "9udj4unjmp9f", "status":"Pending","customerId":"8047380094","locationId":"A3"
},
{
"outdoor": {
"location": {
"type": "Point",
"coordinates": [
-98.5377275,
29.4878928
]
}
},
"geoHash": "9v1zv8p52t8u", "status":"Pending","customerId":"8047380094","locationId":"A4"
},
{
"outdoor": {
"location": {
"type": "Point",
"coordinates": [
-73.7018126,
42.641387
]
}
},
"geoHash": "dreddfeup69m", "status":"Pending","customerId":"8047380094","locationId":"A5"
},
{
"outdoor": {
"location": {
"type": "Point",
"coordinates": [
-111.865295,
33.431942
]
}
},
"geoHash": "9tbqnqn5jtwq", "status":"Active","customerId":"8047380094","locationId":"A6"
},
{
"outdoor": {
"location": {
"type": "Point",
"coordinates": [
-79.810763,
34.174603
]
}
},
"geoHash": "dnp4rv796rtz", "status":"Active","customerId":"8047380094","locationId":"A7"
}
]
Currently we are running 2 queries:
Query 1 - This query will give the counts by status grouped by geoHash substring.
db.locations.aggregate([{"$match": {"customerId": "8047380094"}}, {"$project": {"status": 1, "geoHash": {"$substr": ["$geoHash", 0, 2]}}}, {"$group": {"_id": {"geoHash": "$geoHash", "status": "$status"}, "statusCount": {"$sum": 1}}}],
{
"allowDiskUse": true
});
Output 1:
{ "_id" : { "geoHash" : "dr", "status" : "Active" }, "statusCount" : 1 }
{ "_id" : { "geoHash" : "dr", "status" : "Pending" }, "statusCount" : 1 }
{ "_id" : { "geoHash" : "dn", "status" : "Active" }, "statusCount" : 2 }
{ "_id" : { "geoHash" : "dn", "status" : "Pending" }, "statusCount" : 1 }
{ "_id" : { "geoHash" : "9u", "status" : "Pending" }, "statusCount" : 1 }
{ "_id" : { "geoHash" : "9v", "status" : "Pending" }, "statusCount" : 1 }
{ "_id" : { "geoHash" : "9t", "status" : "Active" }, "statusCount" : 1 }
Query 2 - We have a query to get the first location coordinates for the geohash group.
db.locations.aggregate([{"$match": {"customerId": "8047380094"}}, {"$project": {"geoHash": {"$substr": ["$geoHash", 0, 2]}, "locations": "$outdoor.location.coordinates"}}, {"$group": {"_id": "$geoHash", "locations": {"$push": "$locations"}}}, {"$project": {"_id": 1, "locations": {"$arrayElemAt": ["$locations", 0]}}}],
{
"allowDiskUse": true
});
Output 2:
{ "_id" : "dr", "locations" : [ -92.41151, 35.11683 ] }
{ "_id" : "dn", "locations" : [ -89.58342, 36.859161 ] }
{ "_id" : "9u", "locations" : [ -98.3081936, 26.2143207 ] }
{ "_id" : "9v", "locations" : [ -98.5377275, 29.4878928 ] }
{ "_id" : "9t", "locations" : [ -111.865295, 33.431942 ] }
Question 1:
Is there any we can combine both queries into 1 and get both the outputs in a single query?
Question 2:
If the total count is 1 (not by status), we need to get the locationId also? How can we achieve this in the same query?
In the above case,
for "9u", we need to return A3
for "9v", we need to return A4
for "9t", we need to return A6
Note: We are using spring boot application with spring mongo.

Answer 1

I didn't go what you try to achieve, because the question doesn't mention it. But for you both question, I can answer
You can use $facet to use create multiple aggregation pipeline
By using the first $facet stage, you can use additional stage to get your locationId;
Here is the code
{
$project: {
firstQuery: 1,
secondQuery: {
$map: {
input: "$secondQuery",
as: "s",
in: {
$mergeObjects: [
"$$s",
{
$arrayElemAt: [
{
$map: {
input: {
$filter: {
input: "$firstQuery",
as: "f",
cond: { $eq: ["$$f._id.geoHash", "$$s._id" ] }
}
},
in: { locationId: "$$this.locationId" }
}
},
0
]
}
]
}
}
}
}
}
Working Mongo playground
Note: Make sure { $eq: ["$$f._id.geoHash", "$$s._id" ] } will give one unique object. Else need another idea. And I feel your posted both queries more like same. So there can be a easy solution. But I answered based on the question you posted