Master the art of MongoDB Aggregate with these simple steps!

Question

Master the art of MongoDB Aggregate with these simple steps!

Here is a sample data object:

[
  {
    "_id": "56bab”,
    "region": “AS”,
    “spentOn”: [
      “56bf623a0c90b5”
    ]
  },
  {
    "_id": "57bab",
    "region": "EU",
    "spentOn": [
      "b5”,
      "b6”,
      "b8”,
    ]
  },
  {
    "_id": "58bab",
    "region": "EU",
    "spentOn": [
      "b5”
      "b6”
    ]
  }
]

I am looking to create a MongoDB query (from JS) that will return the most common spentOn value based on a specified region. For instance, if I specify region='EU', I would like to receive back: b6, b5, and b8.

I have referenced this source for guidance and attempted the following code snippet, but I am unsure how to filter by a particular region:

return Q.promise(function(resolve, reject) {
   User.aggregate( [
        { $group: { _id: "$spentOn", count: { "$sum":1 } } },
        { }
    ] );
    resolve();
});

Any assistance on this matter would be greatly appreciated.

Thank you

javascript mongodb

Answer 1

Answer №1

As previously mentioned in the feedback, the key to solving this issue is utilizing the $unwind stage.

Here is a potential solution to address this:

db.users.aggregate([
    {$match:{
        region: "NA"    
    }},
    {$unwind:"$spentOn"},
    {$group:{
        _id: "$spentOn",
        count: {$sum:1}
    }},
    {$sort: {count:-1}}
])

Executing the above query will yield the following outcome:

{ "_id" : "b6", "count" : 2 }
{ "_id" : "b5", "count" : 2 }
{ "_id" : "b8", "count" : 1 }

Answer 2

As previously mentioned in the feedback, the key to solving this issue is utilizing the $unwind stage.

Here is a potential solution to address this:

db.users.aggregate([
    {$match:{
        region: "NA"    
    }},
    {$unwind:"$spentOn"},
    {$group:{
        _id: "$spentOn",
        count: {$sum:1}
    }},
    {$sort: {count:-1}}
])

Executing the above query will yield the following outcome:

{ "_id" : "b6", "count" : 2 }
{ "_id" : "b5", "count" : 2 }
{ "_id" : "b8", "count" : 1 }

Master the art of MongoDB Aggregate with these simple steps!

Answer №1

Similar questions

Will a notification box appear upon submission indicating success or failure?

Tabulator automatically inserted 'numrow' after retrieving the data

Tips for avoiding the default rendering of Nuxt 3 layout?

I am attempting to retrieve the JSON object value from an error response while making a POST request in my Next.js application

Is there a way to connect a Button to a different page in VUE.JS?

What is the best way to send extra parameters to an ajax callback function?

Encountering difficulties parsing XML using NodeJS (with ExpressJS) for MongoDB integration

Using Bootstrap4 to merge rows into a single column or apply rowspan in Bootstrap

Is it possible to utilize AJAX to fetch code from a separate file, view, or page in order to create an experience akin to a single-page application

Learn how to dynamically alter the background color of a webpage by utilizing a JSON API for random color selection

Retrieve selected value from HTML input with datalist and use it as an argument in a method

Designing a system that effectively handles subtract requests from clients on a server

Using JavaScript to create customized checkboxes is a useful way to

Regular expression to limit a string to a maximum of 5 consecutive numeric characters and a total of up to 8 numeric characters

Use Node-RED to fetch JSON or CSV data and store it in InfluxDB

What is the process for testing promise functions that contain an internal promise using Jasmine in an Angular environment?

Is it possible to implement a route within a controller in Express.js?

Website errors appear on the hosted page in <body> section without being present in the code

Is there an "AlphaNumeric" choice available for the AdonisJS 5 Validator?

Having trouble with fetching data in React from a URL?