How to group by and count with mongodb?

Question

I am trying to group by and count with mongodb. Whatever I tried I couldn't do it. This is my query

db.getCollection("requests").find(
 {
 "updatedAt" : {
 "$gt" : ISODate("2020-05-14")
 },
 "status" : "SUGGESTED"
 },
 {
 "user.email" : 1.0,
 "user.name" : 1.0,
 "updatedBy.displayName" : 1.0,
 "requestTerm" : 1.0
 }
)

I would like to group and count based on updatedBy.displayName

So result will be for me distinct displayname ( Column1), count ( number of times )

How can I achieve this?

This is what I tried and it seems it doesn't work

db.requests.aggregate(
 {$match: { "updatedAt" : {
 "$gt" : ISODate("2020-05-14")
 },
 "status" : "SUGGESTED" }},
 {$group: {updatedBy: "$updatedBy.displayName", number: {$sum: 1}}}
)

Answer 1

According to the mongo manual on $group, the command should be like this.

db.requests.aggregate(
 [
 {$match: { 
 "updatedAt" : {"$gt" : ISODate("2020-05-14")},
 "status" : "SUGGESTED" 
 }},
 {$group: {
 _id: {updatedBy: "$updatedBy.displayName"}, 
 number: {$sum: 1}
 }}
 ]
)