What is $match in mongodb?
Docs Home → MongoDB Manual Show $match Filters the documents to pass only the documents that match the specified condition(s) to the next pipeline stage. The
The examples use a collection named
The following operation uses
The
The following example selects documents to process using the
In the aggregation pipeline,
TipWhat can the $match aggregation stage be used for?The $match stage of the pipeline can be used to filter documents so that only ones meeting certain criteria move on to the next stage. In this article, we'll discuss the $match stage in more detail and provide examples that illustrate how to perform match aggregation in MongoDB.
What is use of $Group in MongoDB?The $group stage separates documents into groups according to a "group key". The output is one document for each unique group key. A group key is often a field, or group of fields. The group key can also be the result of an expression.
What is the use of match and group operator in MongoDB?We can group by single as well as multiple field from the collection, we can use $group operator in MongoDB to group fields from the collection and returns the new document as result. We are using $avg, $sum, $max, $min, $push, $last, $first and $addToSet operator with group by in MongoDB.
What is $project in MongoDB?Definition. $project. Passes along the documents with the requested fields to the next stage in the pipeline. The specified fields can be existing fields from the input documents or newly computed fields.
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