aggregate mongo

Mongo scatter -- aggregate & Query, aggregate aggregation Mongo Official Website: http://www.mongodb.org/ Mongo is used in work, but Mongo has not been systematically studied. It only records some knowledge points in the use of Mongo during work

Some records recorded by date in development require statistics in various dimensions, such as day, month, year, and hour ,.. For Grouping statistics, some fields need to be de-duplicated. In the previous [Mongo] grouping statistics by time (group

The NoSQL we use in this article is MongoDB, which is an open-source document database system with the development language C ++. It provides an efficient document-oriented storage structure. The NoSQL we use in this article is MongoDB, which is an

First to https://github.com/mongodb/mongo-csharp-driver/downloads download MONGO official driverRefer to the project when the download is complete Public classConnhelp { Public Static stringConnectionString ="Mongodb://127.0.0.1:27017/qiao";

In the real world, everything has two sides, in the process of the world, and so on! Whether we are in the use of a new language, or a new technology, in the understanding of how exciting it is, make people relaxed, all of the excellent as for, it

This post consists of: http://xinpure.com/2015/01/07/codeigniter-mongodb%e6%89%a9%e5%b1%95%e4%b9%8b%e4%bd%bf%e7%94%a8aggregate% e6%96%b9%e6%b3%95%e5%ae%9e%e7%8e%b0mysql%e7%9a%84sum%e6%96%b9%e6%b3%95/CodeIgniter MongoDB extension using aggregate to

Mongodb Aggregate functions 1. the count function is very understandable. Like other databases, it is used to perform the count operation selectcount (*) fromtab1db. the tab1.count () and above examples are quite understandable, but if there are

MongoDB Aggregation (aggregate) is used primarily to process data (such as statistical averages, sums, and so on) and to return computed data results. Somewhat similar to the count (*) in an SQL statement. Aggregate () method Methods of

MONGO Aggregate query:Db.collection.aggregate ({$group: {_id: ' $id ',//' $_id ' represents the _id column max_value:{$max in the Reference collection: ' $times '}//' $times ' represents Refer to The Times column in the collection}, $match: {times:{$

We know that MongoDB belongs to a document database, and its stored document types are JSON objects. Because of this feature, we often use MONGODB for data access in node. js. But because node. JS is executed asynchronously, this leads us to not