The aggregation pipeline is MongoDB's powerful framework for data processing and analysis — it passes documents through a sequence of stages, each transforming the data (filtering, grouping, computing). It's MongoDB's equivalent of SQL's GROUP BY and complex analytical queries, but more flexible.
The pipeline concept: stages transform data
db..([
{ : { : } },
{ : {
: ,
: { : },
: { : }
}},
{ : { : - } },
{ : }
]);
