Package org.apache.calcite.sql

Class SqlWindowTableFunction

java.lang.Object

org.apache.calcite.sql.SqlOperator

org.apache.calcite.sql.SqlFunction

org.apache.calcite.sql.SqlWindowTableFunction

All Implemented Interfaces:

SqlTableFunction

Direct Known Subclasses:

SqlHopTableFunction, SqlSessionTableFunction, SqlTumbleTableFunction

public class SqlWindowTableFunction
extends SqlFunction
implements SqlTableFunction

Base class for a table-valued function that computes windows. Examples include TUMBLE, HOP and SESSION.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	SqlWindowTableFunction.AbstractOperandMetadata	Partial implementation of operand type checker.

Field Summary

Fields

Modifier and Type	Field	Description
static final SqlReturnTypeInference	ARG0_TABLE_FUNCTION_WINDOWING	Type-inference strategy whereby the row type of a table function call is a ROW, which is combined from the row type of operand #0 (which is a TABLE) and two additional fields.
protected static final String	PARAM_DATA	The data source which the table function computes with.
protected static final String	PARAM_KEY	The session key(s), only used for SESSION window.
protected static final String	PARAM_OFFSET	The optional align offset for each window.
protected static final String	PARAM_SIZE	The window duration INTERVAL.
protected static final String	PARAM_SLIDE	The slide interval, only used for HOP window.
protected static final String	PARAM_TIMECOL	The time attribute column.

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

kind, MDX_PRECEDENCE, NL

Constructor Summary

Constructors

Constructor	Description
SqlWindowTableFunction(String name, SqlOperandMetadata operandMetadata)	Creates a window table function with a given name.

Method Summary

Modifier and Type	Method	Description
boolean	argumentMustBeScalar(int ordinal)	Returns whether the ordinalth argument to this operator must be scalar (as opposed to a query).
@Nullable SqlOperandMetadata	getOperandTypeChecker()
SqlReturnTypeInference	getRowTypeInference()	Returns the record type of the table yielded by this function when applied to given arguments.

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

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

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

acceptCall, acceptCall, adjustType, allowsFraming, checkOperandCount, checkOperandTypes, constructArgNameList, constructArgTypeList, constructOperandList, createCall, createCall, createCall, createCall, createCall, createCall, createCall, deriveOperandType, equals, getAllowedSignatures, getAllowedSignatures, getKind, getLeftPrec, getMonotonicity, getMonotonicity, getName, getOperandCountRange, getOperandTypeInference, getReturnTypeInference, getRightPrec, getSignatureTemplate, getStrongPolicyInference, hashCode, inferReturnType, inferReturnType, isAggregator, isDeterministic, isDynamicFunction, isGroup, isGroupAuxiliary, isName, isSymmetrical, leftPrec, not, preValidateCall, requiresDecimalExpansion, requiresOrder, requiresOver, reverse, rewriteCall, rightPrec, toString, unparseListClause, unparseListClause, validateOperands, validRexOperands

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.calcite.sql.SqlTableFunction

tableCharacteristic

Field Details

PARAM_DATA

protected static final String PARAM_DATA

The data source which the table function computes with.

See Also:

• Constant Field Values

PARAM_TIMECOL

protected static final String PARAM_TIMECOL

The time attribute column. Also known as the event time.

See Also:

• Constant Field Values

PARAM_SIZE

protected static final String PARAM_SIZE

The window duration INTERVAL.

See Also:

• Constant Field Values

PARAM_OFFSET

protected static final String PARAM_OFFSET

The optional align offset for each window.

See Also:

• Constant Field Values

PARAM_KEY

protected static final String PARAM_KEY

The session key(s), only used for SESSION window.

See Also:

• Constant Field Values

PARAM_SLIDE

protected static final String PARAM_SLIDE

The slide interval, only used for HOP window.

See Also:

• Constant Field Values

ARG0_TABLE_FUNCTION_WINDOWING

public static final SqlReturnTypeInference ARG0_TABLE_FUNCTION_WINDOWING

Type-inference strategy whereby the row type of a table function call is a ROW, which is combined from the row type of operand #0 (which is a TABLE) and two additional fields. The fields are as follows:

1. window_start: TIMESTAMP type to indicate a window's start
2. window_end: TIMESTAMP type to indicate a window's end

Constructor Details

SqlWindowTableFunction

public SqlWindowTableFunction(String name,
 SqlOperandMetadata operandMetadata)

Creates a window table function with a given name.

Method Details

getOperandTypeChecker

public @Nullable SqlOperandMetadata getOperandTypeChecker()

Overrides:

getOperandTypeChecker in class SqlOperator

getRowTypeInference

public SqlReturnTypeInference getRowTypeInference()

Description copied from interface: SqlTableFunction

Returns the record type of the table yielded by this function when applied to given arguments. Only literal arguments are passed, non-literal are replaced with default values (null, 0, false, etc).

Specified by:

getRowTypeInference in interface SqlTableFunction

Returns:

strategy to infer the row type of a call to this function

argumentMustBeScalar

public boolean argumentMustBeScalar(int ordinal)

Returns whether the ordinalth argument to this operator must be scalar (as opposed to a query).

If true (the default), the validator will attempt to convert the argument into a scalar sub-query, which must have one column and return at most one row.

Operators such as SELECT and EXISTS override this method.

Overrides because the first parameter of table-value function windowing is an explicit TABLE parameter, which is not scalar.

Overrides:

argumentMustBeScalar in class SqlOperator