org.apache.calcite.sql

Class SqlAggFunction

java.lang.Object

org.apache.calcite.sql.SqlOperator

org.apache.calcite.sql.SqlFunction

org.apache.calcite.sql.SqlAggFunction

Direct Known Subclasses:

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

public abstract class SqlAggFunction
extends SqlFunction

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

Field Summary

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) Creates a user-defined SqlAggFunction.
protected	SqlAggFunction(String name, SqlKind kind, SqlReturnTypeInference returnTypeInference, SqlOperandTypeInference operandTypeInference, SqlOperandTypeChecker operandTypeChecker, SqlFunctionCategory funcType) Creates a built-in SqlAggFunction.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	isAggregator() Returns whether this operator is an aggregate function.
boolean	isQuantifierAllowed() Returns whether this function allows a DISTINCT or ALL quantifier.
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, getParamTypes, getSqlIdentifier, getSyntax, unparse, validateQuantifier

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

SqlAggFunction

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

Creates a built-in SqlAggFunction.

SqlAggFunction

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

Creates a user-defined SqlAggFunction.

Method Detail

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)