使用Spring Data MongoDB进行组聚合 [英] Group aggregation using spring data mongodb

问题描述

我试图使用日期对象中的年份值作为键来编写组聚合查询，但是由于某种原因，我遇到了此异常.

I tried to write a group aggregation query using the year value from a date object as a key, but for some reason I'm getting this exception.

org.springframework.data.mapping.PropertyReferenceException: No property year(invoiceDate)

这是我要复制的mongo查询:

Here is the mongo query which I'm trying to replicate:

db.collection.aggregate([
   {
     $match:
     {
       "status": "Active"
     }
   },
   {
     $group:
     {
      "_id":{$year:"$invoiceDate"}
     }
  },
  {
    $sort:
    {
      "_id" : -1
    }
  }
])

这是我的Java实现:

And this is my Java implementation:

Aggregation aggregation = Aggregation.newAggregation(
    match(new Criteria().andOperator(criteria())),
    Aggregation.group("year(invoiceDate)")
).withOptions(newAggregationOptions().allowDiskUse(true).build());

我也没有找到对分组结果进行排序的方法.

I also didn't find a way how I can apply the sorting on the results from the grouping.

推荐答案

您基本上是在寻找extractYear()，它映射到

You're basically looking for extractYear() which maps to the $year operator with MongoDB:

Aggregation aggregation = Aggregation.newAggregation(
    Aggregation.match(new Criteria().andOperator(criteria())),
    Aggregation.project().and("invoiceDate").extractYear().as("_id"),
    Aggregation.group("_id"),
    Aggregation.sort(Sort.Direction.DESC, "_id)
)

这通常需要进入 $project 为了使助手们高兴.

This generally needs to go into a $project in order to make the helpers happy.

如果您确实要在 $group 然后您可以添加一个自定义操作表达式:

If you really want the expression within the $group then you can add a custom operation expression:

Aggregation aggregation = Aggregation.newAggregation(
  Aggregation.match(new Criteria().andOperator(criteria())),
  new AggregationOperation() {
    @Override
    public Document toDocument(AggregationOperationContext aggregationOperationContext) {
      return new Document("$group",
        new Document("_id", new Document("$year","$invoiceDate") )
      );
    }
  },
  Aggregation.sort(Sort.Direction.DESC, "_id)
)

这篇关于使用Spring Data MongoDB进行组聚合的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！