mongodb aggregate unwind

/*** 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*

Recently has been using MongoDB, sometimes will need to use statistics, on the Internet to check some information, the most suitable for use is to use aggregate, the following introduction of their own use of experience. MongoDB

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

Aggregate is the more important of the many tools that MongoDB provides, similar to the one in SQL statements GROUP BY . The aggregation tool allows developers to manipulate data in the database directly using MongoDB native commands, and aggregates

Http://www.cnblogs.com/qq78292959/p/4440679.html Recently has been using MongoDB, sometimes need to use statistics, on the Internet to check some information, the most suitable use is to use aggregate, the following introduction of their own use

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. Download extract MongoDB, configure environment variablesTAR-ZXVF mongodb-linux-x86_64-rhel62-3.2.7.tgzExport Path=/bin: $PATH2. Create a data Save directoryMkdir-p/data/db3.mongodb Boot./mongod//Default boot./mongod--dbpath=/data/db//Start

Aggregate contains the different types in 3:1. Pipeline2. Single function aggregation (COUNT,GROUP,DISTINCT)3. Map-reducePipeline expressionA pipe expression can only manipulate documents that are currently in the pipeline and cannot represent other

MongoDB database data aggregation & amp; Pipe operations, mongodb database AggregationThe data aggregation process for pipeline operations on mongodb usually works with pipeline operations. The pipeline operation concept of mongodb is similar to the

In the previous article we talked about MongoDB advanced query: http://blog.csdn.net/stronglyh/article/details/46817789This article is about MongoDB aggregation.A: MongoDB has a lot of aggregation framework, so that the transformation and