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
Column	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.