Spring mongo aggregate get count and date by a date range

Question

I want to get how many products sold in a specific date range.

final TypedAggregation<Product> otpTypedAggregation = newAggregation(Product.class,
                    match(Criteria.where(CREATED_AT).gte(fromDate).lte(toDate)),
                    project(CREATED_AT)
                            .andExpression("dayOfMonth(createdAt)").as("day")
                            .andExpression("month(createdAt)").as("month")
                            .andExpression("year(createdAt)").as("year"),
                    group(fields().and("day").and("month").and("year")).first("sold_at").as("sold_at")
                            .count().as("count"),
                    sort(new Sort(ASC, "sold_at"))
            );
 mongoTemplate.aggregate(otpTypedAggregation, Data.class).getMappedResults();

After the execution, I get an output like this

[Data(sold_at=Mon Jan 06 04:38:18 IST 2020, count=1), Data(sold_at=Mon Jan 06 10:23:03 IST 2020, count=1), Data(sold_at=Tue Jan 07 09:46:54 IST 2020, count=2)]

But this is how I wish to recieve the data:

[Data(sold_at=Mon Jan 06 2020, count=2),Data(sold_at=Tue Jan 07 2020, count=2)]

So how to modify the code to get the above result?

Answer 1

Provide sample data to check if it's valid solution.

Note: If this is valid solution, I can translate into Spring-Data syntax.

db.product.aggregate([
  {
    $match: {}
  },
  {
    $project: {
      day: {
        $dayOfMonth: "$createdAt"
      },
      month: {
        $month: "$createdAt"
      },
      year: {
        $year: "$createdAt"
      }
    }
  },
  {
    $group: {
      _id: {
        day: "$day",
        month: "$month",
        year: "$year"
      },
      count: {
        $sum: 1
      }
    }
  },
  {
    $project: {
      _id: 0,
      sold_at: {
        $dateFromParts: {
          year: "$_id.year",
          month: "$_id.month",
          day: "$_id.day"
        }
      },
      count: 1
    }
  },
  {
    $sort: {
      sold_at: 1
    }
  }
])

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