org.eigenbase.sql
Class SqlRankFunction

java.lang.Object
  org.eigenbase.sql.SqlOperator
      org.eigenbase.sql.SqlFunction
          org.eigenbase.sql.SqlAggFunction
              org.eigenbase.sql.SqlRankFunction

All Implemented Interfaces:

Aggregation

public class SqlRankFunction
extends SqlAggFunction

Operator which aggregates sets of values into a result.

Since:

Jun 3, 2005

Version:

$Id: //open/dev/farrago/src/org/eigenbase/sql/SqlRankFunction.java#10 $

Author:

jack

Field Summary

private RelDataType

type

Fields inherited from class org.eigenbase.sql.SqlOperator

MaxPrec, NL

Constructor Summary

SqlRankFunction(String name)

Method Summary

SqlOperandCountRange	getOperandCountRange() Returns a constraint on the number of operands expected by this operator.
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.
boolean	isAggregator() Returns whether this operator is an aggregate function.
void	validateCall(SqlCall call, SqlValidator validator, SqlValidatorScope scope, SqlValidatorScope operandScope) Validates a call to this operator.

Methods inherited from class org.eigenbase.sql.SqlAggFunction

getStartParameterTypes, isQuantifierAllowed

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, getOperandTypeChecker, getOperandTypeInference, getReturnTypeInference, getRightPrec, getSignatureTemplate, hashCode, inferReturnType, inferReturnType, 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

SqlRankFunction

public SqlRankFunction(String name)

Method Detail

getOperandCountRange

public SqlOperandCountRange getOperandCountRange()

Description copied from class: SqlOperator

Returns a constraint on the number of operands expected by this operator. Subclasses may override this method; when they don't, the range is derived from the SqlOperandTypeChecker associated with this operator.

Overrides:

getOperandCountRange in class SqlOperator

Returns:

acceptable range

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

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

isAggregator

public boolean isAggregator()

Description copied from class: SqlOperator

Returns whether this operator is an aggregate function. By default, subclass type is used (an instance of SqlAggFunction is assumed to be an aggregator; anything else is not).

Overrides:

isAggregator in class SqlOperator

Returns:

whether this operator is an aggregator

validateCall

public void validateCall(SqlCall call,
                         SqlValidator validator,
                         SqlValidatorScope scope,
                         SqlValidatorScope operandScope)

Description copied from class: SqlOperator

Validates a call to this operator.

This method should not perform type-derivation or perform validation related related to types. That is done later, by SqlOperator.deriveType(SqlValidator, SqlValidatorScope, SqlCall). This method should focus on structural validation.

A typical implementation of this method first validates the operands, then performs some operator-specific logic. The default implementation just validates the operands.

This method is the default implementation of SqlCall.validate(org.eigenbase.sql.validate.SqlValidator, org.eigenbase.sql.validate.SqlValidatorScope); but note that some sub-classes of SqlCall never call this method.

Overrides:

validateCall in class SqlAggFunction

Parameters:

call - the call to this operator

validator - the active validator

scope - validator scope

operandScope - validator scope in which to validate operands to this call; usually equal to scope, but not always because some operators introduce new scopes

See Also:

SqlNode.validateExpr(SqlValidator, SqlValidatorScope), SqlOperator.deriveType(SqlValidator, SqlValidatorScope, SqlCall)