mongodb aggregate group example

/*** 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 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

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

In MongoDB, there are three ways to do this, but most of the three are silly, this article is to sum up the difference between the following three ways ~ 1. Polymeric Framework Aggregate Pipeline 2. MapReduce 3. Aggregation command

Original link http://www.cnblogs.com/zhangzili/p/4975080.htmlMongoDB knowledge points at a glance1. Start the MongoDB database:Go to the MongoDB installation directory and execute the following commandC:\Program

This article introduced the MongoDB in the MapReduce implementation of data aggregation method, we mentioned MongoDB in the data aggregation operation of a way--mapreduce, but in most of the day-to-day use of the process, We do not need to use

This article mainly introduces the PHP operation MongoDB implementation of adding and removing functions, combined with examples of the form of a summary of the PHP operation MongoDB Common skills, and with PHP7 operation MongoDB method, with a

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

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

This article mainly introduces the PHP operation MongoDB implementation of adding and removing functions, combined with examples of the form of a summary of the PHP operation MongoDB Common skills, and with PHP7 operation MongoDB method, with a