org.apache.calcite.sql

Class SqlWindow

java.lang.Object

org.apache.calcite.sql.SqlNode

org.apache.calcite.sql.SqlCall

org.apache.calcite.sql.SqlWindow

All Implemented Interfaces:

Cloneable

public class SqlWindow
extends SqlCall

SQL window specification.

For example, the query

SELECT sum(a) OVER (w ROWS 3 PRECEDING)
 FROM t
 WINDOW w AS (PARTITION BY x, y ORDER BY z),
     w1 AS (w ROWS 5 PRECEDING UNBOUNDED FOLLOWING)

declares windows w and w1, and uses a window in an OVER clause. It thus contains 3 SqlWindow objects.

Field Summary

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

EMPTY_ARRAY, pos

Constructor Summary

Constructors

Constructor and Description
SqlWindow(SqlParserPos pos, SqlIdentifier declName, SqlIdentifier refName, SqlNodeList partitionList, SqlNodeList orderList, SqlLiteral isRows, SqlNode lowerBound, SqlNode upperBound, SqlLiteral allowPartial) Creates a window.

Method Summary

Methods

Modifier and Type	Method and Description
static SqlWindow	create(SqlIdentifier declName, SqlIdentifier refName, SqlNodeList partitionList, SqlNodeList orderList, SqlLiteral isRows, SqlNode lowerBound, SqlNode upperBound, SqlLiteral allowPartial, SqlParserPos pos)
static SqlNode	createBound(SqlLiteral range)
static SqlNode	createCurrentRow(SqlParserPos pos)
SqlWindow	createCurrentRowWindow(String columnName) Creates a window (RANGE columnName CURRENT ROW).
static SqlNode	createFollowing(SqlNode e, SqlParserPos pos)
static SqlNode	createPreceding(SqlNode e, SqlParserPos pos)
static SqlNode	createUnboundedFollowing(SqlParserPos pos)
static SqlNode	createUnboundedPreceding(SqlParserPos pos)
SqlWindow	createUnboundedPrecedingWindow(String columnName) Creates a window (RANGE columnName UNBOUNDED PRECEDING).
boolean	equalsDeep(SqlNode node, boolean fail) Overridden method to specifically check only the right subtree of a window definition.
SqlIdentifier	getDeclName()
SqlKind	getKind() Returns the type of node this is, or SqlKind.OTHER if it's nothing special.
SqlNode	getLowerBound()
List<SqlNode>	getOperandList()
SqlOperator	getOperator()
SqlNodeList	getOrderList()
SqlNodeList	getPartitionList()
SqlIdentifier	getRefName()
SqlNode	getUpperBound()
SqlCall	getWindowCall()
boolean	isAllowPartial() Returns whether partial windows are allowed.
boolean	isAlwaysNonEmpty() Returns if the window is guaranteed to have rows.
static boolean	isCurrentRow(SqlNode node) Returns whether an expression represents the "CURRENT ROW" bound.
boolean	isRows()
static boolean	isUnboundedFollowing(SqlNode node) Returns whether an expression represents the "UNBOUNDED FOLLOWING" bound.
static boolean	isUnboundedPreceding(SqlNode node) Returns whether an expression represents the "UNBOUNDED PRECEDING" bound.
SqlWindow	overlay(SqlWindow that, SqlValidator validator) Creates a new window by combining this one with another.
void	populateBounds() Fill in missing bounds.
void	setDeclName(SqlIdentifier declName)
void	setLowerBound(SqlNode lowerBound)
void	setOperand(int i, SqlNode operand) Changes the value of an operand.
void	setUpperBound(SqlNode upperBound)
void	setWindowCall(SqlCall windowCall)
void	unparse(SqlWriter writer, int leftPrec, int rightPrec) Writes a SQL representation of this node to a writer.
void	validate(SqlValidator validator, SqlValidatorScope scope) Validates this call.

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

accept, clone, findValidOptions, getCallSignature, getFunctionQuantifier, getMonotonicity, isCountStar, isExpanded, operand, operandCount

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

clone, cloneArray, equalDeep, equalDeep, getParserPosition, isA, toSqlString, toSqlString, toString, validateExpr

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

SqlWindow

public SqlWindow(SqlParserPos pos,
         SqlIdentifier declName,
         SqlIdentifier refName,
         SqlNodeList partitionList,
         SqlNodeList orderList,
         SqlLiteral isRows,
         SqlNode lowerBound,
         SqlNode upperBound,
         SqlLiteral allowPartial)

Creates a window.

Method Detail

create

public static SqlWindow create(SqlIdentifier declName,
               SqlIdentifier refName,
               SqlNodeList partitionList,
               SqlNodeList orderList,
               SqlLiteral isRows,
               SqlNode lowerBound,
               SqlNode upperBound,
               SqlLiteral allowPartial,
               SqlParserPos pos)

getOperator

public SqlOperator getOperator()

Specified by:

getOperator in class SqlCall

getKind

public SqlKind getKind()

Description copied from class: SqlNode

Returns the type of node this is, or SqlKind.OTHER if it's nothing special.

Overrides:

getKind in class SqlNode

Returns:

a SqlKind value, never null

See Also:

SqlNode.isA(java.util.Set<org.apache.calcite.sql.SqlKind>)

getOperandList

public List<SqlNode> getOperandList()

Specified by:

getOperandList in class SqlCall

setOperand

public void setOperand(int i,
              SqlNode operand)

Description copied from class: SqlCall

Changes the value of an operand. Allows some rewrite by SqlValidator; use sparingly.

Overrides:

setOperand in class SqlCall

Parameters:

i - Operand index

operand - Operand value

unparse

public void unparse(SqlWriter writer,
           int leftPrec,
           int rightPrec)

Description copied from class: SqlNode

Writes a SQL representation of this node to a writer.

The leftPrec and rightPrec parameters give us enough context to decide whether we need to enclose the expression in parentheses. For example, we need parentheses around "2 + 3" if preceded by "5 *". This is because the precedence of the "*" operator is greater than the precedence of the "+" operator.

The algorithm handles left- and right-associative operators by giving them slightly different left- and right-precedence.

If SqlWriter.isAlwaysUseParentheses() is true, we use parentheses even when they are not required by the precedence rules.

For the details of this algorithm, see SqlCall.unparse(org.apache.calcite.sql.SqlWriter, int, int).

Overrides:

unparse in class SqlCall

Parameters:

writer - Target writer

leftPrec - The precedence of the SqlNode immediately preceding this node in a depth-first scan of the parse tree

rightPrec - The precedence of the SqlNode immediately

getDeclName

public SqlIdentifier getDeclName()

setDeclName

public void setDeclName(SqlIdentifier declName)

getLowerBound

public SqlNode getLowerBound()

setLowerBound

public void setLowerBound(SqlNode lowerBound)

getUpperBound

public SqlNode getUpperBound()

setUpperBound

public void setUpperBound(SqlNode upperBound)

isAlwaysNonEmpty

public boolean isAlwaysNonEmpty()

Returns if the window is guaranteed to have rows. This is useful to refine data type of window aggregates. For instance sum(non-nullable) over (empty window) is NULL.

Returns:

true when the window is non-empty

See Also:

Window.Group.isAlwaysNonEmpty(), SqlOperatorBinding.getGroupCount(), SqlValidatorImpl.resolveWindow(SqlNode, org.apache.calcite.sql.validate.SqlValidatorScope, boolean)

isRows

public boolean isRows()

getOrderList

public SqlNodeList getOrderList()

getPartitionList

public SqlNodeList getPartitionList()

getRefName

public SqlIdentifier getRefName()

setWindowCall

public void setWindowCall(SqlCall windowCall)

getWindowCall

public SqlCall getWindowCall()

createCurrentRow

public static SqlNode createCurrentRow(SqlParserPos pos)

createUnboundedFollowing

public static SqlNode createUnboundedFollowing(SqlParserPos pos)

createUnboundedPreceding

public static SqlNode createUnboundedPreceding(SqlParserPos pos)

createFollowing

public static SqlNode createFollowing(SqlNode e,
                      SqlParserPos pos)

createPreceding

public static SqlNode createPreceding(SqlNode e,
                      SqlParserPos pos)

createBound

public static SqlNode createBound(SqlLiteral range)

isCurrentRow

public static boolean isCurrentRow(SqlNode node)

Returns whether an expression represents the "CURRENT ROW" bound.

isUnboundedPreceding

public static boolean isUnboundedPreceding(SqlNode node)

Returns whether an expression represents the "UNBOUNDED PRECEDING" bound.

isUnboundedFollowing

public static boolean isUnboundedFollowing(SqlNode node)

Returns whether an expression represents the "UNBOUNDED FOLLOWING" bound.

overlay

public SqlWindow overlay(SqlWindow that,
                SqlValidator validator)

Creates a new window by combining this one with another.

For example,

WINDOW (w PARTITION BY x ORDER BY y)
   overlay
   WINDOW w AS (PARTITION BY z)

yields

WINDOW (PARTITION BY z ORDER BY y)

Does not alter this or the other window.

Returns:

A new window

equalsDeep

public boolean equalsDeep(SqlNode node,
                 boolean fail)

Overridden method to specifically check only the right subtree of a window definition.

Overrides:

equalsDeep in class SqlCall

Parameters:

node - The SqlWindow to compare to "this" window

fail - Whether to throw if not equal

Returns:

boolean true if all nodes in the subtree are equal

isAllowPartial

public boolean isAllowPartial()

Returns whether partial windows are allowed. If false, a partial window (for example, a window of size 1 hour which has only 45 minutes of data in it) will appear to windowed aggregate functions to be empty.

validate

public void validate(SqlValidator validator,
            SqlValidatorScope scope)

Description copied from class: SqlCall

Validates this call.

The default implementation delegates the validation to the operator's SqlOperator.validateCall(org.apache.calcite.sql.SqlCall, org.apache.calcite.sql.validate.SqlValidator, org.apache.calcite.sql.validate.SqlValidatorScope, org.apache.calcite.sql.validate.SqlValidatorScope). Derived classes may override (as do, for example SqlSelect and SqlUpdate).

Overrides:

validate in class SqlCall

scope - Validator

createCurrentRowWindow

public SqlWindow createCurrentRowWindow(String columnName)

Creates a window (RANGE columnName CURRENT ROW).

Parameters:

columnName - Order column

createUnboundedPrecedingWindow

public SqlWindow createUnboundedPrecedingWindow(String columnName)

Creates a window (RANGE columnName UNBOUNDED PRECEDING).

Parameters:

columnName - Order column

populateBounds

public void populateBounds()

Fill in missing bounds. Default bounds are "BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW" when ORDER BY present and "BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING" when no ORDER BY present.