PG_AGGREGATE

pg_aggregate records information about aggregation functions. Each entry in pg_aggregate is an extension of an entry in pg_proc. The pg_proc entry carries the aggregate's name, input and output data types, and other information that is similar to ordinary functions.

**Table 1** PG_AGGREGATE columns
Name	Type	Reference	Description
aggfnoid	regproc	PG_PROC.oid	PG_PROC OID of the aggregate function
aggtransfn	regproc	PG_PROC.oid	Transition function
aggcollectfn	regproc	PG_PROC.oid	Aggregate function
aggfinalfn	regproc	PG_PROC.oid	Final function (zero if none)
aggsortop	oid	PG_OPERATOR.oid	Associated sort operator (zero if none)
aggtranstype	oid	PG_TYPE.oid	Data type of the aggregate function's internal transition (state) data
agginitval	text	-	Initial value of the transition state. This is a text column containing the initial value in its external string representation. If this column is null, the transition state value starts out null.
agginitcollect	text	-	Initial value of the collection state. This is a text column containing the initial value in its external string representation. If this column is null, the collection state value starts out null.