org.eigenbase.sql.fun
Class SqlSumEmptyIsZeroAggFunction

java.lang.Object
  org.eigenbase.sql.SqlOperator
      org.eigenbase.sql.SqlFunction
          org.eigenbase.sql.SqlAggFunction
              org.eigenbase.sql.fun.SqlSumEmptyIsZeroAggFunction

All Implemented Interfaces:

Aggregation

public class SqlSumEmptyIsZeroAggFunction
extends SqlAggFunction

Sum0 is an aggregator which returns the sum of the values which go into it like Sum. It differs in that when no non null values are applied zero is returned instead of null. Can be used along with Count to implement Sum.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/sql/fun/SqlSumEmptyIsZeroAggFunction.java#4 $

Author:

jhahn

Field Summary

private RelDataType

type

Fields inherited from class org.eigenbase.sql.SqlOperator

MaxPrec, NL

Constructor Summary

SqlSumEmptyIsZeroAggFunction(RelDataType type)

Method Summary

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.
OJClass[]	getStartParameterTypes()
RelDataType	getType()

Methods inherited from class org.eigenbase.sql.SqlAggFunction

isQuantifierAllowed, validateCall

Methods inherited from class org.eigenbase.sql.SqlFunction

deriveType, getFunctionType, getNameAsId, getParamTypes, getSqlIdentifier, getSyntax, unparse, validateQuantifier

Methods inherited from class org.eigenbase.sql.SqlOperator

acceptCall, acceptCall, adjustType, argumentMustBeScalar, checkOperandCount, checkOperandTypes, createCall, createCall, createCall, createCall, equals, getAllowedSignatures, getAllowedSignatures, getKind, getLeftPrec, getMonotonicity, getName, getOperandCountRange, getOperandTypeChecker, getOperandTypeInference, getReturnTypeInference, getRightPrec, getSignatureTemplate, hashCode, inferReturnType, inferReturnType, isAggregator, isDeterministic, isDynamicFunction, isName, leftPrec, preValidateCall, requiresDecimalExpansion, rewriteCall, rightPrec, toString, unparseListClause, unparseListClause, validateOperands

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.eigenbase.rel.Aggregation

getName

Field Detail

type

private final RelDataType type

Constructor Detail

SqlSumEmptyIsZeroAggFunction

public SqlSumEmptyIsZeroAggFunction(RelDataType type)

Method Detail

getParameterTypes

public RelDataType[] getParameterTypes(RelDataTypeFactory typeFactory)

Description copied from interface: Aggregation

Returns the parameter types accepted by this Aggregation.

Parameters:

typeFactory - Type factory to create the types

Returns:

Array of parameter types

getType

public RelDataType getType()

getReturnType

public RelDataType getReturnType(RelDataTypeFactory typeFactory)

Description copied from interface: Aggregation

Returns the type of the result yielded by this Aggregation.

Parameters:

typeFactory - Type factory to create the type

Returns:

Result type

getStartParameterTypes

public OJClass[] getStartParameterTypes()

Overrides:

getStartParameterTypes in class SqlAggFunction