MongoDB query find, sum and count

My document of a collection is a block in blockchain with fields {height, gasUsed, timestamp}

I want to get the total gas used (sum of gasUsed) and total count, given a particular day.

Below is my query to get all blocks within 4 Jan 2022

    db.getCollection('blocks').find({
        timestamp: {
            $gte: new Date(2022, 0, 4),
            $lt: new Date(2022, 0, 5)
        }
    }

How could I get the total count and sum of gasUsed as well (within 4 Jan 2022)?

Solution 1:

You can do it with Aggregation framework $match and $group:

db.collection.aggregate([
  {
    "$match": {
      "$and": [
        {
          "timestamp": {
            "$gte": new Date("2022-01-01")
          }
        },
        {
          "timestamp": {
            "$lt": new Date("2022-01-03")
          }
        }
      ]
    }
  },
  {
    "$group": {
      "_id": null,
      "total_count": { "$sum": 1 },
      "total_gas":   { "$sum": "$gasUsed" }
    }
  }
])

Working example