org.apache.calcite.sql

Class SqlAggFunction

java.lang.Object

org.apache.calcite.sql.SqlOperator

org.apache.calcite.sql.SqlFunction

org.apache.calcite.sql.SqlAggFunction

All Implemented Interfaces:

Context, Wrapper

Direct Known Subclasses:

SqlAbstractGroupFunction, SqlAvgAggFunction, SqlCountAggFunction, SqlCovarAggFunction, SqlFirstLastValueAggFunction, SqlHistogramAggFunction, SqlLeadLagAggFunction, SqlMinMaxAggFunction, SqlNtileAggFunction, SqlRankFunction, SqlSingleValueAggFunction, SqlSumAggFunction, SqlSumEmptyIsZeroAggFunction, SqlUserDefinedAggFunction

public abstract class SqlAggFunction
extends SqlFunction
implements Context

Abstract base class for the definition of an aggregate function: an operator which aggregates sets of values into a result.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	requiresOrder
private boolean	requiresOver

Fields inherited from class org.apache.calcite.sql.SqlOperator

kind, MDX_PRECEDENCE, NL

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SqlAggFunction(String name, SqlIdentifier sqlIdentifier, SqlKind kind, SqlReturnTypeInference returnTypeInference, SqlOperandTypeInference operandTypeInference, SqlOperandTypeChecker operandTypeChecker, SqlFunctionCategory funcType) Deprecated.
protected	SqlAggFunction(String name, SqlIdentifier sqlIdentifier, SqlKind kind, SqlReturnTypeInference returnTypeInference, SqlOperandTypeInference operandTypeInference, SqlOperandTypeChecker operandTypeChecker, SqlFunctionCategory funcType, boolean requiresOrder, boolean requiresOver) Creates a built-in or user-defined SqlAggFunction or window function.
protected	SqlAggFunction(String name, SqlKind kind, SqlReturnTypeInference returnTypeInference, SqlOperandTypeInference operandTypeInference, SqlOperandTypeChecker operandTypeChecker, SqlFunctionCategory funcType) Deprecated.

Method Summary

Modifier and Type	Method and Description
boolean	allowsFilter() Whether this aggregate function allows a FILTER (WHERE ...) clause.
List<RelDataType>	getParameterTypes(RelDataTypeFactory typeFactory) Deprecated.
RelDataType	getReturnType(RelDataTypeFactory typeFactory) Deprecated.
boolean	isAggregator() Returns whether this operator is an aggregate function.
boolean	isQuantifierAllowed() Returns whether this function allows a DISTINCT or ALL quantifier.
boolean	requiresOrder() Returns whether this is a window function that requires ordering.
boolean	requiresOver() Returns whether this is a window function that requires an OVER clause.
<T> T	unwrap(Class<T> clazz) Finds an instance of an interface implemented by this object, or returns null if this object does not support that interface.
void	validateCall(SqlCall call, SqlValidator validator, SqlValidatorScope scope, SqlValidatorScope operandScope) Validates a call to this operator.

Methods inherited from class org.apache.calcite.sql.SqlFunction

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

Methods inherited from class org.apache.calcite.sql.SqlOperator

acceptCall, acceptCall, adjustType, allowsFraming, argumentMustBeScalar, checkOperandCount, checkOperandTypes, constructArgNameList, constructArgTypeList, constructOperandList, createCall, createCall, createCall, createCall, equals, getAllowedSignatures, getAllowedSignatures, getKind, getLeftPrec, getMonotonicity, getMonotonicity, getName, getOperandCountRange, getOperandTypeChecker, getOperandTypeInference, getReturnTypeInference, getRightPrec, getSignatureTemplate, hashCode, inferReturnType, inferReturnType, isDeterministic, isDynamicFunction, isGroup, isGroupAuxiliary, isName, leftPrec, needsSpace, preValidateCall, requiresDecimalExpansion, rewriteCall, rightPrec, toString, unparseListClause, unparseListClause, validateOperands, validRexOperands

Methods inherited from class java.lang.Object

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

Field Detail

requiresOrder

private final boolean requiresOrder

requiresOver

private final boolean requiresOver

Constructor Detail

SqlAggFunction

@Deprecated
protected SqlAggFunction(String name,
                                     SqlKind kind,
                                     SqlReturnTypeInference returnTypeInference,
                                     SqlOperandTypeInference operandTypeInference,
                                     SqlOperandTypeChecker operandTypeChecker,
                                     SqlFunctionCategory funcType)

Deprecated.

Creates a built-in SqlAggFunction.

SqlAggFunction

@Deprecated
protected SqlAggFunction(String name,
                                     SqlIdentifier sqlIdentifier,
                                     SqlKind kind,
                                     SqlReturnTypeInference returnTypeInference,
                                     SqlOperandTypeInference operandTypeInference,
                                     SqlOperandTypeChecker operandTypeChecker,
                                     SqlFunctionCategory funcType)

Deprecated.

Creates a user-defined SqlAggFunction.

SqlAggFunction

protected SqlAggFunction(String name,
                         SqlIdentifier sqlIdentifier,
                         SqlKind kind,
                         SqlReturnTypeInference returnTypeInference,
                         SqlOperandTypeInference operandTypeInference,
                         SqlOperandTypeChecker operandTypeChecker,
                         SqlFunctionCategory funcType,
                         boolean requiresOrder,
                         boolean requiresOver)

Creates a built-in or user-defined SqlAggFunction or window function.

A user-defined function will have a value for sqlIdentifier; for a built-in function it will be null.

Method Detail

unwrap

public <T> T unwrap(Class<T> clazz)

Description copied from interface: Wrapper

Finds an instance of an interface implemented by this object, or returns null if this object does not support that interface.

Specified by:

unwrap in interface Wrapper

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).

Per SQL:2011, there are aggregate functions and window functions. Every aggregate function (e.g. SUM) is also a window function. There are window functions that are not aggregate functions, e.g. RANK, NTILE, LEAD, FIRST_VALUE.

Collectively, aggregate and window functions are called analytic functions. Despite its name, this method returns true for every analytic function.

Overrides:

isAggregator in class SqlOperator

Returns:

whether this operator is an analytic function (aggregate function or window function)

See Also:

SqlOperator.requiresOrder()

isQuantifierAllowed

public boolean isQuantifierAllowed()

Description copied from class: SqlFunction

Returns whether this function allows a DISTINCT or ALL quantifier. The default is false; some aggregate functions return true.

Overrides:

isQuantifierAllowed in class SqlFunction

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.apache.calcite.sql.validate.SqlValidator, org.apache.calcite.sql.validate.SqlValidatorScope); but note that some sub-classes of SqlCall never call this method.

Overrides:

validateCall in class SqlFunction

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)

requiresOrder

public final boolean requiresOrder()

Description copied from class: SqlOperator

Returns whether this is a window function that requires ordering.

Per SQL:2011, 2, 6.10: "If <ntile function>, <lead or lag function>, RANK or DENSE_RANK is specified, then the window ordering clause shall be present."

Overrides:

requiresOrder in class SqlOperator

See Also:

SqlOperator.isAggregator()

requiresOver

public final boolean requiresOver()

Description copied from class: SqlOperator

Returns whether this is a window function that requires an OVER clause.

For example, returns true for RANK, DENSE_RANK and other ranking functions; returns false for SUM, COUNT, MIN, MAX, AVG (they can be used as non-window aggregate functions).

If requiresOver returns true, then SqlOperator.isAggregator() must also return true.

Overrides:

requiresOver in class SqlOperator

See Also:

SqlOperator.allowsFraming(), SqlOperator.requiresOrder()

getParameterTypes

@Deprecated
public List<RelDataType> getParameterTypes(RelDataTypeFactory typeFactory)

Deprecated.

getReturnType

@Deprecated
public RelDataType getReturnType(RelDataTypeFactory typeFactory)

Deprecated.

allowsFilter

public boolean allowsFilter()

Whether this aggregate function allows a FILTER (WHERE ...) clause.