Stages

The aggregation pipeline allows any combination/ordering of the following stages.

	Stage	Description
	Filter	Return records that match a critera
	Group	Calculate measure(s) in total or across mutually-exclusive groups
	Aggregate	Like Group but allows overlapping groups, pivot and more
	Sort	Sort records by one or more fields
	Limit	Return a maximum of N records
	Skip	Return all records excluding the first N
	Add fields	Add computed fields
	Drop fields	Drop fields
	Rename fields	Rename fields
	Add window fields	Add fields using windowed operations
	Select	Select fields from input records (and optionally add fields)
	Stack	Append rows from a second set of records
	Join	Append columns from a second set of records
	UnPivot	Consolidate columns into rows