Package io.trino.sql.planner.iterative.rule

Class UnwrapCastInComparison

java.lang.Object

io.trino.sql.planner.iterative.rule.ExpressionRewriteRuleSet

io.trino.sql.planner.iterative.rule.UnwrapCastInComparison

public class UnwrapCastInComparison
extends ExpressionRewriteRuleSet

Given s of type S, a constant expression t of type T, and when an implicit cast exists between S->T, converts expression of the form:

 CAST(s as T) = t
 

into

 s = CAST(t as S)
 

For example:

 CAST(x AS bigint) = bigint '1'
 

turns into

 x = smallint '1'
 

It can simplify expressions that are known to be true or false, and remove the comparisons altogether. For example, give x::smallint, for an expression like:

 CAST(x AS bigint) > bigint '10000000'
 

Nested Class Summary

Nested classes/interfaces inherited from class io.trino.sql.planner.iterative.rule.ExpressionRewriteRuleSet

ExpressionRewriteRuleSet.ExpressionRewriter

Constructor Summary

Constructors

Constructor	Description
UnwrapCastInComparison(Metadata metadata, TypeOperators typeOperators, TypeAnalyzer typeAnalyzer)

Method Summary

Modifier and Type	Method	Description
static Expression	unwrapCasts(Session session, Metadata metadata, TypeOperators typeOperators, TypeAnalyzer typeAnalyzer, TypeProvider types, Expression expression)

Methods inherited from class io.trino.sql.planner.iterative.rule.ExpressionRewriteRuleSet

aggregationExpressionRewrite, filterExpressionRewrite, joinExpressionRewrite, projectExpressionRewrite, rules, valuesExpressionRewrite

Methods inherited from class java.lang.Object

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

Constructor Detail

UnwrapCastInComparison

public UnwrapCastInComparison(Metadata metadata,
                              TypeOperators typeOperators,
                              TypeAnalyzer typeAnalyzer)

Method Detail

unwrapCasts

public static Expression unwrapCasts(Session session,
                                     Metadata metadata,
                                     TypeOperators typeOperators,
                                     TypeAnalyzer typeAnalyzer,
                                     TypeProvider types,
                                     Expression expression)