Azure Cosmos DB mongo db api: attribute wise count for the records

Question

Hi,

I have my data stored in azure cosmos db (Mongo db API), sample of the data is as shown below:
currently, i query based on the apptype, my requirement is to show the count of each attribute as well. eg: in the example below, there are two records with "ct" as 4000 and 1 record of 7000. I have to show the count against all the attributes in my document.
Would need help in how can we achieve this without compromising with the performance?

{
"_id" : ObjectId("5ad88af611f6f87cba45c8a5"),
"name" : "C-PHB-A",
"apptype":"AreaLight",
"ct" : [
4000,
5000
],
"voltages" : [
"120-277"
],
"types" : [
"Linear"
]
},

{
"_id" : ObjectId("5ad88af611f6f87cba45c8a5"),

"name" : "12-PHB-A",   
"apptype":"AreaLight",  
"ct" : [  
	4000,  
	5000,  
	7000  
],  
"voltages" : [  
	"120-277"  
],  
"types" : [  
	"Linear"  
]  

}

Answer 1

Finally, I was able to sort out. Mongo db has support for $facet attribute which allows you to do aggregation in multiple stages:
db.getCollection("testfixturefamilies").aggregate(
[
{
"$match" : {
"applicationType" : "Highbay"
}
},
{
"$facet" : {
"types" : [
{
"$unwind" : "$colorTempeartures"
},
{
"$group" : {
"_id" : "$colorTempeartures",
"name" : {
"$first" : "$colorTempeartures"
},
"count" : {
"$sum" : 1.0
}
}
}
],
"voltages" : [
{
"$unwind" : "$voltages"
},
{
"$group" : {
"_id" : "$voltages",
"name" : {
"$first" : "$voltages"
},
"count" : {
"$sum" : 1.0
}
}
}]

);

Advantage of using facets is that the data is just obtained once and is passed to the different stages, This is the output you will get:
{
"colorTemperatures" : [
{
"_id" : "4000",
"name" : "4000",
"count" : 1.0
}
],
"voltages" : [
{
"_id" : "120-277",
"name" : "120-277V",
"count" : 2.0
}
]
}