What is Mongoose aggregation?

Can you explain what Mongoose aggregation is?

Mongoose aggregation is a powerful feature in MongoDB that allows you to process data records and return computed results. It uses a pipeline approach to transform and combine data.

How does the aggregation pipeline work?

The aggregation pipeline consists of multiple stages, each performing a specific operation on the data, such as filtering, grouping, or sorting. Each stage passes its output to the next stage.

Can you give me an example of an aggregation query?

Sure! An example would be using the $group stage to calculate the total sales per product: db.sales.aggregate([{ $group: { _id: '$productId', totalSales: { $sum: '$amount' } } }]).

What are some common stages used in aggregation?

Common stages include $match, $group, $sort, $project, and $lookup, each serving different purposes in data processing.