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.
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. |