MongoDB 对 SpringDataMongoDB 的聚合查询

Question

我有以下 MongoDB 聚合查询，并希望它具有等效的 SpringData Mongodb 查询。

MongoDB 聚合查询：

db.response.aggregate(
        // Pipeline
        [
            // Stage 1 : Group by Emotion & Month
            {
                $group: {
                    _id: {
                        emotion: "$emotion",
                        category: "$category"
                    },
                    count: {
                        $sum: 1
                    },
                    point: {
                        $first: '$point'
                    }
                }
            },
            // Stage 2 : Total Points
            {
                $addFields: {
                    "totalPoint": {
                        $multiply: ["$point", "$count"]
                    }
                }
            },
                        // Stage3 : Group By Category - Overall Response Total & totalFeedbacks
            {
                $group: {
                    _id: '$_id.category',
                    totalFeedbacks: {
                        $sum: "$count"
                    },
                    overallResponseTotal: {
                        $sum: "$totalPoint"
                    }
                }
            },
                        // Stage4 - Overall Response Total & totalFeedbacks
            {
                $project: {
                    _id: 1,
                    overallResponseTotal: '$overallResponseTotal',
                    maxTotalFrom: {
                        "$multiply": ["$totalFeedbacks", 3.0]
                    },
                    percent: {
                        "$multiply": [{
                            "$divide": ["$overallResponseTotal", "$maxTotalFrom"]
                        }, 100.0]
                    }
                }
            },
                        // Stage4 - Percentage Monthwise
                {
                    $project: {
                        _id: 1,
                        overallResponseTotal: 1,
                        maxTotalFrom: 1,
                        percent: {
                            "$multiply": [{
                                "$divide": ["$overallResponseTotal", "$maxTotalFrom"]
                            }, 100.0]
                        }
                    }

                }
            ]
);

我已经在 Spring Data 中尝试过它的等价物，但在如何将“$addFields”转换为 java 代码的问题上停留在第 2 阶段。虽然我在多个网站上搜索它，但找不到任何有用的东西。请参阅我的阶段 1 等效 Java 代码。

//Stage 1 -Group By Emotion and Category and return it's count

GroupOperation groupEmotionAndCategory = Aggregation.group("emotion","category").count().as("count").first("point")
                        .as("point");

Aggregation aggregation = Aggregation.newAggregation(groupEmotionAndCategory);

AggregationResults<CategoryWiseEmotion> output = mongoTemplate.aggregate(aggregation, Response.class, CategoryWiseEmotion.class);

任何帮助将不胜感激。

Answer 1

$addFields 还不是 Spring Data Mongodb 的 supported。

一种解决方法是pass the raw aggregation pipeline to Spring。

但由于第 1 阶段之后的字段数量有限，您也可以将第 2 阶段降级为projection：

{
    $project: {
        // _id is included by default
        "count" : 1, // include count
        "point" : 1, // include point
        "totalPoint": {
            $multiply: ["$point", "$count"] // compute totalPoint
        }
    }
}

我自己没有测试过，但是这个预测应该转化为类似的东西：

ProjectionOperation p = project("count", "point").and("point").multiply(Fields.field("count")).as("totalPoint");

然后您可以类似地翻译阶段 3、4 和 5，并将整个管道传递给 Aggregation.aggregate()。