Chapter 5. Queries and aggregation


In this chapter
  • Querying an e-commerce data model
  • The MongoDB query language in detail
  • Aggregation with map-reduce and group


MongoDB doesn’t use SQL. Rather, it features its own JSON-like query language. We’ve been exploring this language throughout the book, but here we turn to some meatier, real-world examples. In particular, we’re going to revisit the e-commerce data model introduced in the last chapter and present a variety of queries against it. Among the queries you’ll practice are _id lookups, ranges, ordering, and projections. We’ll also survey the MongoDB query language as a whole, looking at each available query operator in detail.

In addition to queries, we’ll cover the related topic of aggregation. ...

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