mongodb aggregation framework

MongoDB Study Notes-aggregation The latest new project to use mysql has not forgotten yet. The summary records the following MongoDB aggregation. AggregationIt refers to various operations that can process batch records and return computing results.

Mongodb advanced 2: mongodb aggregation and mongodb advanced AggregationIn the previous article we talked about mongodb's advanced query: http://blog.csdn.net/stronglyh/article/details/46817789 This article introduces mongodb aggregation. I. mongodb

PrefaceThere are 3 days to end in 2014, and this month's plan has been completed in addition to the summary of MongoDB's other plans. Recently, lazy research on MongoDB has been suspended for a long time. In the last three days, the study of MongoDB

/*** MongoDB $type operator*/ /*** The $type operator is based on the Bson type to retrieve the matching data type in the collection and returns the result.* The types of MongoDB that can be used are shown in the following table:* Type Number Notes*

The recent new project to use MySQL, while not yet forgotten, summarizes the following MongoDB aggregations.aggregation refers to the various operations that can handle batch records and return results. MongoDB provides rich aggregation operations

in the two previous articles the basic aggregation function of data aggregation in MongoDB count, distinct, group > and the MapReduce of data aggregation in MongoDB >, we've provided two implementations for data aggregation, and today, in this

1. Aggregation Frameworkusing the aggregation framework to transform and combine documents in a collection, you can create a pipeline (pipeline) with multiple artifacts to process a series of documents. These artifacts include filtering (filtering),

An aggregation framework is a new framework for data aggregation. It is similar to a data processing pipeline. Each document uses a pipeline composed of multiple nodes. Each node has its own special An aggregation framework is a new framework for

Aggregation IntroductionThe aggregation operation is the operation that comes out of the data record and returns the computed result. MongoDB provides a rich aggregation operation to detect and execute calculations on datasets. Data aggregation

Group of aggregation operationsGrammar:Db.collection.group ({Key:{key1:1,key2:1},cond:{},Reduce:function (Curr,result) {},initial:{},Finalize:function () {}})Key: Group FieldCond: Query criteriaReduce: aggregate functionInitial: