The $group stage separates documents into groups according to a "group key". The output is one document for each unique group key. $count-accumulator · $Accumulator · $mergeObjects · $addToSet (aggregation)

The $group stage groups the documents by date and calculates the total sale amount, average quantity, and total count of the documents in each group.

In this article, I will explain the main principles of building aggregate queries in MongoDB and how to take advantage of indexes for speeding them up.

Aggregation $group. This aggregation stage groups documents by the unique _id expression provided. Don't confuse this _id expression with the _id ObjectId ...

8 июл. 2024 г. · The $group command in MongoDB's aggregation framework is a powerful tool for performing complex data analysis and summarization.

22 февр. 2023 г. · I m working with MongoDB but i m facing problem with $project not displaying the data after $group is executed . My database look like this

16 апр. 2014 г. · I am playing around with MongoDB trying to figure out how to do a simple SELECT province, COUNT(*) FROM contest GROUP BY province But I can't seem to figure it ... MongoDB Aggregation: How to group in array value? mongodb group by multiple fields, return newest document with ... MongoDB aggregate pipeline group - Stack Overflow Group collection certain field in one array - mongodb Другие результаты с сайта stackoverflow.com

10 авг. 2023 г. · Aggregation to group by multiple fields in a document · Push them into an array · Unwind it · Group up by name and status then flatten out ( ...

The $group operator groups similar data by some specified expression and groups the document for each distinct grouping.

For a group of documents, as with the $group and $setWindowFields stages, $last returns the entire array from the last document. It does not traverse array ...