consulta mongodb vs mysql

1. Efetuar cálculo:SUM((credit*(100-rate))/100) .
2. Agrupar por $accountNum e agregar SUM para resultMultiply .

db.collection.aggregate([
  {
    $match: {
      rate: {
        $ne: 0
      }
    }
  },
  {
    $addFields: {
      resultMultiply: {
        $divide: [
          {
            $multiply: [
              "$credit",
              {
                "$subtract": [
                  100,
                  "$rate"
                ]
              }
            ]
          },
          100
        ]
      }
    }
  },
  {
    $group: {
      _id: "$accountNum",
      total: {
        $sum: "$resultMultiply"
      }
    }
  }
])

[
  {
    "_id": 2,
    "total": 1.5
  },
  {
    "_id": 1,
    "total": 5.5
  }
]