org.apache.calcite.rel.rules

Class SubQueryRemoveRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.SubQueryRemoveRule

public abstract class SubQueryRemoveRule
extends RelOptRule

Transform that converts IN, EXISTS and scalar sub-queries into joins.

Sub-queries are represented by RexSubQuery expressions.

A sub-query may or may not be correlated. If a sub-query is correlated, the wrapped RelNode will contain a RexCorrelVariable before the rewrite, and the product of the rewrite will be a Correlate. The Correlate can be removed using RelDecorrelator.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	SubQueryRemoveRule.ReplaceSubQueryShuttle Shuttle that replaces occurrences of a given RexSubQuery with a replacement expression.

Field Summary

Fields

Modifier and Type	Field and Description
static SubQueryRemoveRule	FILTER
static SubQueryRemoveRule	JOIN
static SubQueryRemoveRule	PROJECT

Fields inherited from class org.apache.calcite.plan.RelOptRule

description, operands, relBuilderFactory

Constructor Summary

Constructors

Constructor and Description
SubQueryRemoveRule(RelOptRuleOperand operand, RelBuilderFactory relBuilderFactory, String description) Creates a SubQueryRemoveRule.

Method Summary

Modifier and Type	Method and Description
protected RexNode	apply(RexSubQuery e, Set<CorrelationId> variablesSet, RelOptUtil.Logic logic, RelBuilder builder, int inputCount, int offset)
private RexInputRef	field(RelBuilder builder, int inputCount, int offset) Returns a reference to a particular field, by offset, across several inputs on a RelBuilder's stack.
private static List<RexNode>	fields(RelBuilder builder, int fieldCount) Returns a list of expressions that project the first fieldCount fields of the top input on a RelBuilder's stack.

Methods inherited from class org.apache.calcite.plan.RelOptRule

any, convert, convert, convertList, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, matches, none, onMatch, operand, operand, operand, operand, operand, some, toString, unordered

Methods inherited from class java.lang.Object

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

Field Detail

PROJECT

public static final SubQueryRemoveRule PROJECT

FILTER

public static final SubQueryRemoveRule FILTER

JOIN

public static final SubQueryRemoveRule JOIN

Constructor Detail

SubQueryRemoveRule

public SubQueryRemoveRule(RelOptRuleOperand operand,
                          RelBuilderFactory relBuilderFactory,
                          String description)

Creates a SubQueryRemoveRule.

Parameters:

operand - root operand, must not be null

description - Description, or null to guess description

relBuilderFactory - Builder for relational expressions

Method Detail

apply

protected RexNode apply(RexSubQuery e,
                        Set<CorrelationId> variablesSet,
                        RelOptUtil.Logic logic,
                        RelBuilder builder,
                        int inputCount,
                        int offset)

field

private RexInputRef field(RelBuilder builder,
                          int inputCount,
                          int offset)

Returns a reference to a particular field, by offset, across several inputs on a RelBuilder's stack.

fields

private static List<RexNode> fields(RelBuilder builder,
                                    int fieldCount)

Returns a list of expressions that project the first fieldCount fields of the top input on a RelBuilder's stack.