Java Mongo DB聚合管道 - $ sum在使用$ Undind时无法正常工作吗？

发布于 2025-02-08 21:47:43 字数 1483 浏览 2 评论 0原文

我目前正在我的一个Java脚本中使用MongoDB聚合管道。

输入数据可以简化为不同客户的订单列表。例如：

_id	customerId	OrderId	运输	金额
1	123	A12B4	货运1，装运	2 30.00
2	456	A14HF	装运3	40.00
2	123	A27JD	货运4	20.00 20.00 20.00

_id，customerId和OrderId和orderId是字符串，货物的数量是多大的类型，并且货物是多数的实体。 - 班级的班级。现在，我想汇总此内容，并向每个客户提供他们所花费的总量和所有货物的总量。像这样的第一个客户：

{customerId：123，发货：[Shipment1，Shipment2，shipment2，shipment4]，金额：50.00}

数据以JSON格式进行

[
 {
   "_id": 1,
   "customerId": 123,
   "orderId": "a12b4",
   "shipments": ["shipment1","shipment2"],
   "amount": 30
 },
 {
   "_id": 2,
   "customerId": 456,
   "orderId": "a14hf",
   "shipments": ["shipment3"],
   "amount": 40
 },
 {
   "_id": 3,
   "customerId": 123,
   "orderId": "a27jd",
   "shipments": ["shipment4"],
   "amount": 20
 }
]

，所以我做到了：

Aggregates.unwind("$shipments"),
Aggregates.group("$customerId",
     Accumulators.sum("amount","$amount"),
     Accumulators.addToSet("shipments", "$shipments")),
Aggregates.out("test_output")

这就是我的问题所在的地方：

只要我保留我的放松陈述，总和> 的用法就不会返回正确的结果。但是，当我用另一个我不必放松的领域取代货物时，它可以正常工作。

任何提示都将不胜感激。

原文

I am currently working on a mongoDB aggregation pipeline in one of my Java scripts.

The input data can be simplified to a list of orders of different customers. Such as:

_id	customerId	orderId	shipments	amount
1	123	a12b4	shipment1, shipment2	30.00
2	456	a14hf	shipment3	40.00
2	123	a27jd	shipment4	20.00

_id, customerId, and orderId are strings, the amount a number of type Long, and the shipments are entities of a custom-made class called shipment. Now, I want to aggregate this and show, for every customerId, the total amount of what they spent and all the shipments. Like this for the first customer:

{customerId: 123, shipments: [shipment1, shipment2, shipment4], amount: 50.00}

Data in json format

[
 {
   "_id": 1,
   "customerId": 123,
   "orderId": "a12b4",
   "shipments": ["shipment1","shipment2"],
   "amount": 30
 },
 {
   "_id": 2,
   "customerId": 456,
   "orderId": "a14hf",
   "shipments": ["shipment3"],
   "amount": 40
 },
 {
   "_id": 3,
   "customerId": 123,
   "orderId": "a27jd",
   "shipments": ["shipment4"],
   "amount": 20
 }
]

So, I did this:

Aggregates.unwind("$shipments"),
Aggregates.group("$customerId",
     Accumulators.sum("amount","$amount"),
     Accumulators.addToSet("shipments", "$shipments")),
Aggregates.out("test_output")

And this is where my question comes in:
Are the usages of unwind and sum exclusive?

As long as I keep my unwind statement, the sum function does not return the correct result. But it works just fine as soon as I replace shipments by another field that I do not have to unwind.

Any hints would be greatly appreciated.

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月棠 2025-02-15 21:47:43

查询

Undind将创建许多重复，但您不需要它
和sum，并为每个客户收集货物
可以group 阵列和与[]联合使其设置（不是重复的装运）

Playmongo

aggregate(
[{"$group": 
   {"_id": "$customerId",
    "shipments": {"$push": "$shipments"},
    "total-amound": {"$sum": "$amount"}}},
 {"$set": 
   {"shipments": 
     {"$setUnion": 
       [{"$reduce": 
           {"input": "$shipments",
            "initialValue": [],
            "in": {"$concatArrays": ["$value", "$this"]}}}, []]}}}])

Query

unwind will create many duplicated but you dont need it
you can group and sum, and collect the shipments for each customer
and then reduce to flatten the array, and union with [] to make it set (not duplicate shipments)

Playmongo

aggregate(
[{"$group": 
   {"_id": "$customerId",
    "shipments": {"$push": "$shipments"},
    "total-amound": {"$sum": "$amount"}}},
 {"$set": 
   {"shipments": 
     {"$setUnion": 
       [{"$reduce": 
           {"input": "$shipments",
            "initialValue": [],
            "in": {"$concatArrays": ["$value", "$this"]}}}, []]}}}])

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