aggregate

R2026b

Run MongoDB aggregation pipeline

Since R2026b

Syntax

data = aggregate(mongodbconn,collectname,pipeline)

Description

data = aggregate(mongodbconn,collectname,pipeline) returns aggregated data from the specified MongoDB^® collection by running an aggregation pipeline. Use aggregate when you want MongoDB to filter, group, or summarize data before returning results to MATLAB^®.

Examples

Aggregate MongoDB Collection Data

Create a collection of sample documents, run a multi‑stage aggregation pipeline to filter and summarize the data, and return the results.

Use the mongoc function to create the database connection.

port = 27017;
dbname = "mongotest";

mongodbconn = mongoc(getSecret("mongoc_server"),port,dbname, ... 
    UserName = getSecret("mongoc_username"), ... 
    Password = getSecret("mongoc_password"));

Insert sample documents into a collection.

collectname = "employeeCollection";

docs(1) = struct("name", "Alice", "department", "Engineering", "status", "active", "salary", 90000);
docs(2) = struct("name", "Bob",   "department", "Engineering", "status", "inactive", "salary", 85000);
docs(3) = struct("name", "Carol", "department", "HR",          "status", "active",   "salary", 60000);
docs(4) = struct("name", "David", "department", "HR",          "status", "active",   "salary", 62000);
docs(5) = struct("name", "Eve",   "department", "Sales",       "status", "active",   "salary", 70000);
docs(6) = struct("name", "Frank", "department", "Sales",       "status", "inactive", "salary", 68000);

createCollection(mongodbconn,collectname);
insert(mongodbconn,collectname,docs);

Run a three-stage aggregation pipeline to process the data.

pipeline = {
    '{ "$match": { "status": "active" } }'
    '{ "$group": { "_id": "$department", "totalSalary": { "$sum": "$salary" } } }'
    '{ "$sort": { "totalSalary": -1 } }'
    };

data = aggregate(mongodbconn,collectname,pipeline)

data = 3×1 struct array with fields:
    _id
    totalSalary

Close the database connection.

dropCollection(mongodbconn,collectname);
close(mongodbconn);

Input Arguments

mongodbconn — MongoDB C++ interface connection

connection object

MongoDB C++ interface connection, specified as a connection object.

collectname — MongoDB collection name

string scalar

MongoDB collection name, specified as a string scalar. The aggregation pipeline runs on documents in this collection.

pipeline — Aggregation pipeline

string scalar | string array | cell array of character vectors

Aggregation pipeline, specified as a string scalar, string array, or cell array of character vectors. This input defines an ordered sequence of MongoDB aggregation stages, expressed using JSON-style syntax, that transform documents in the collection. Each stage performs a specific operation and passes its output to the next stage.

For example, { "$match": { "status": "active" } } creates a single-stage pipeline that filters documents based on the specified condition. Pipelines often include multiple stages, such as $match, $group, and $sort.

Example: {'{ "$sort": { "totalSalary": -1 } }'}

Output Arguments

data — Aggregated data

structure | structure array | cell array of structures

Aggregated data from the specified collection, represented as MATLAB structures:

• Structure for a single document

• Structure array for multiple documents with the same fields

• Cell array of structures for documents with different fields

Each structure represents a JSON-style document returned by the aggregation pipeline.

Version History

Introduced in R2026b