mongodb aggregate project group

/*** 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

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

#MongoDb Aggregation method group Aggrate mapreduce#1. Group (shard not supported, distributed calculation)*Grammatical StructureDb.collection.group ({key:{category:1},//Classification according to categorycond:{shop_price:{$gt: 20}},//a product

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

0) MONGO: Connect MongoDB database via client1) Show DBS---Display the currently created database2) Use test---Create or switch databases3) Db.dropdatabase ()--Delete the current database3) Show Collections: Displays the collection created by the

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

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

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.

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