Question

任何人都可以帮助我，我的大脑堆叠使这个集合mapreduce，我如何获得PurchaseAmount，PurchaseReturnAmount和TotalAmount，键“年”。</ strong>

{ "_id" : { "OwnerId" : "coba@aja.com", "SupplierId" : BinData(3,"AYC8In8bFkGYNx34poQLlg=="), "GroupId" : BinData(3,"mzWBCilngEGd72YpeyijcQ=="), "ProductId" : BinData(3,"gZ2g/syue06v8b88+0pqRA=="), "Date" : ISODate("2013-01-15T00:00:00Z") }, "value" : { "OwnerId" : "oetawan@dokuku.com", "Date" : ISODate("2013-01-15T00:00:00Z"), "SupplierId" : BinData(3,"AYC8In8bFkGYNx34poQLlg=="), "SupplierName" : "Matahari", "GroupId" : BinData(3,"mzWBCilngEGd72YpeyijcQ=="), "GroupCode" : "Umum", "GroupName" : "Umum", "ProductId" : BinData(3,"gZ2g/syue06v8b88+0pqRA=="), "ProductCode" : null, "ProductBarcode" : "IPAD2", "ProductName" : "iPad 2", "PurchaseAmount" : 19500000, "PurchaseReturnAmount" : 0, "TotalAmount" : 19500000 }

} 我想使用这个地图reduce to C＃

Answer 1

这是使用MR的shell示例。当然，您也可以使用聚合框架来完成它，但可能您希望在后台运行它;

db.so.mapReduce(
        function () { /* map */
            var key = this._id.Date.getFullYear();
            emit(key, { PurchaseAmount:this.value.PurchaseAmount, PurchaseReturnAmount:this.value.PurchaseReturnAmount, TotalAmount:this.value.TotalAmount } );
        }, 
        function (key, array) { /* reduce*/
            var result = { PurchaseAmount: 0, PurchaseReturnAmount: 0, TotalAmount: 0 };
            for (var i = 0; i < array.length; i++) {
                {
                    result.PurchaseAmount += array[i].PurchaseAmount;
                    result.PurchaseReturnAmount += array[i].PurchaseReturnAmount;
                    result.TotalAmount += array[i].TotalAmount;
                }
            }
            return result;
        },
        {
            out: "so_mr_example",
            query:{}
        }
);

db.so_mr_example.find();

产生类似的东西;

{ "_id" : 2013, "value" : { "PurchaseAmount" : 39000000, "PurchaseReturnAmount" : 0, "TotalAmount" : 39000000 } }
{ "_id" : 2014, "value" : { "PurchaseAmount" : 19500000, "PurchaseReturnAmount" : 0, "TotalAmount" : 19500000 } }

我如何使Mapreduce逐年获得成功？

1 个答案: