aggregate¶

aggregate¶

New in version 2.1.0.

aggregate implements the aggregation framework. Consider the following prototype form:

{ aggregate: "[collection]", pipeline: [pipeline] }

Where [collection] specifies the name of the collection that contains the data that you wish to aggregate. The pipeline argument holds an array that contains the specification for the aggregation operation. Consider the following example from the aggregation documentation.

copy

db.runCommand(
{ aggregate : "article", pipeline : [
  { $project : {
     author : 1,
     tags : 1,
  } },
  { $unwind : "$tags" },
  { $group : {
     _id : "$tags",
     authors : { $addToSet : "$author" }
  } }
 ] }
);

More typically this operation would use the aggregate() helper in the mongo shell, and would resemble the following:

copy

db.article.aggregate(
  { $project : {
     author : 1,
     tags : 1,
  } },
  { $unwind : "$tags" },
  { $group : {
     _id : "$tags",
     authors : { $addToSet : "$author" }
  } }
);

For more aggregation documentation, please see:

← addShard applyOps (internal) →