Tags → #aggregation
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Bending Arrays to Your Will: $map, $filter, $reduce
Stop looping in Node.js. Learn how to transform arrays directly inside the database for maximum performance.
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Joins in MongoDB: The $lookup Stage
Yes, MongoDB has joins! Learn how to combine data from multiple collections using the powerful $lookup stage.
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Mastering $group and $project
How to build powerful reports using MongoDB Aggregation. Summing, averaging, and reshaping your data.
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The Aggregation Pipeline: SQL Power in MongoDB
Forget find(). If you want to do analytics, reports, or complex transformations, you need the Aggregation Framework. We cover $match, $group, and $sort.