org.eigenbase.rel
Interface Aggregation

All Known Implementing Classes:

SqlAggFunction, SqlAvgAggFunction, SqlCountAggFunction, SqlFirstLastValueAggFunction, SqlHistogramAggFunction, SqlMinMaxAggFunction, SqlRankFunction, SqlSingleValueAggFunction, SqlSumAggFunction, SqlSumEmptyIsZeroAggFunction

public interface Aggregation

An Aggregation aggregates a set of values into one value.

It is used, via a AggregateCall, in an AggregateRel relational operator.

Since:

26 January, 2001

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/Aggregation.java#13 $

Author:

jhyde

Method Summary

String	getName() Returns the name of this Aggregation
RelDataType[]	getParameterTypes(RelDataTypeFactory typeFactory) Returns the parameter types accepted by this Aggregation.
RelDataType	getReturnType(RelDataTypeFactory typeFactory) Returns the type of the result yielded by this Aggregation.

Method Detail

getParameterTypes

RelDataType[] getParameterTypes(RelDataTypeFactory typeFactory)

Returns the parameter types accepted by this Aggregation.

Parameters:

typeFactory - Type factory to create the types

Returns:

Array of parameter types

getReturnType

RelDataType getReturnType(RelDataTypeFactory typeFactory)

Returns the type of the result yielded by this Aggregation.

Parameters:

typeFactory - Type factory to create the type

Returns:

Result type

getName

String getName()

Returns the name of this Aggregation

Returns:

name of this aggregation