MongoDB $bucket

Place numeric values into ranges with boundaries you choose.

Each boundary begins an inclusive range and the following boundary ends it. Use `output` accumulators to calculate a count, total, or other measure for each range.

Stages are the top-level steps in a pipeline. Each stage receives documents, changes the stream in one specific way, and passes its output to the next stage.

Course use: Exercise 09.

{ $bucket: {
  groupBy: "$total",
  boundaries: [0, 100, 200, 1000],
  output: { count: { $sum: 1 } }
} }