Group result by 15 minutes time interval in MongoDb

Question

I have a \"status\" collection like this strcture -

{
    _id: ObjectId(\"545a0b63b03dbcd1238b4567\"),
    status: 1004,
    comment: \"Rem dolor ipsam place         


        

Answer 1

@Neil Lunn's answer at https://stackoverflow.com/a/26814496/8474325 for MongoDb 4.x upwards is fantastic. But there is a small mistake in the code where he uses ObjectId for the aggregation. The Line { "$toDate": "_id" } has to be changed to { "$toDate": "$_id" } for the code to work.

Here's the corrected code.

db.collection.aggregate([
    { "$group": {
      "_id": {
          "$toDate": {
              "$subtract": [
                  { "$toLong": { "$toDate": "$_id" }  },
                  { "$mod": [ { "$toLong": { "$toDate": "$_id" } }, 1000 * 60 * 15 ] }
              ]
          }
      },
      "count": { "$sum": 1 }
   }}
])