org.eigenbase.sql.fun
Class SqlMinMaxAggFunction

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

All Implemented Interfaces:

Aggregation

public class SqlMinMaxAggFunction
extends SqlAggFunction

Definition of the MIN and MAX aggregate functions, returning the returns the smallest/largest of the values which go into it.

There are 3 forms:

sum(primitive type)

values are compared using <

sum(Comparable)

values are compared using Comparable.compareTo(T)

sum(Comparator, Object)

the Comparator.compare(T, T) method of the comparator is used to compare pairs of objects. The comparator is a startup argument, and must therefore be constant for the duration of the aggregation.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/sql/fun/SqlMinMaxAggFunction.java#17 $

Author:

jhyde

Field Summary

RelDataType[]	argTypes
private boolean	isMin
private int	kind
static int	MINMAX_COMPARABLE
static int	MINMAX_COMPARATOR
static int	MINMAX_INVALID
static int	MINMAX_PRIMITIVE

Fields inherited from class org.eigenbase.sql.SqlOperator

MaxPrec, NL

Constructor Summary

SqlMinMaxAggFunction(RelDataType[] argTypes, boolean isMin, int kind)

Method Summary

int	getMinMaxKind()
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()
boolean	isMin()

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

MINMAX_INVALID

public static final int MINMAX_INVALID

See Also:

Constant Field Values

MINMAX_PRIMITIVE

public static final int MINMAX_PRIMITIVE

See Also:

Constant Field Values

MINMAX_COMPARABLE

public static final int MINMAX_COMPARABLE

See Also:

Constant Field Values

MINMAX_COMPARATOR

public static final int MINMAX_COMPARATOR

See Also:

Constant Field Values

argTypes

public final RelDataType[] argTypes

isMin

private final boolean isMin

kind

private final int kind

Constructor Detail

SqlMinMaxAggFunction

public SqlMinMaxAggFunction(RelDataType[] argTypes,
                            boolean isMin,
                            int kind)

Method Detail

isMin

public boolean isMin()

getMinMaxKind

public int getMinMaxKind()

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

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