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https://issues.apache.org/jira/browse/CALCITE-2745?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16723372#comment-16723372
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Julian Hyde commented on CALCITE-2745:
--------------------------------------
No, it is not acceptable.
Making Rex a dynamically-typed language increases the burden for everyone else.
For dynamic record types, we should adopt something similar to how one does
dynamic typing in java - either treat everything as an object, or use casts
preceded by an "instanceof" check. Now, we currently don't have an "instanceof"
operator. I wish we had one. I don't even know what it should be called in SQL.
I suspect that Oracle added one as part of their "object" support in Oracle 8.
> RexSimplify fails with ClassCastException when the expression contains
> comparisons of operands with different types
> -------------------------------------------------------------------------------------------------------------------
>
> Key: CALCITE-2745
> URL: https://issues.apache.org/jira/browse/CALCITE-2745
> Project: Calcite
> Issue Type: Bug
> Reporter: Volodymyr Vysotskyi
> Assignee: Julian Hyde
> Priority: Major
>
> {{RexSimplify}} fails with {{ClassCastException}} when the expression
> contains predicates with comparisons of operands with different types.
> Test to reproduce this issue (placed into {{JdbcAdapterTest}}):
> {code:sql}
> @Test public void testSeveralTypesComparison() {
> CalciteAssert.model(JdbcTest.FOODMART_MODEL)
> .query("SELECT \"full_name\" FROM \"employee\" WHERE "
> + "\"employee_id\" = '1' and \"employee_id\" > 0")
> .returns("full_name=Sheri Nowmer\n");
> }
> {code}
> It fails with the error:
> {noformat}
> Caused by: java.lang.ClassCastException: org.apache.calcite.util.NlsString
> cannot be cast to java.math.BigDecimal
> at java.math.BigDecimal.compareTo(BigDecimal.java:220)
> at
> org.apache.calcite.rex.RexSimplify.processRange(RexSimplify.java:1780)
> at
> org.apache.calcite.rex.RexSimplify.simplifyAnd2ForUnknownAsFalse(RexSimplify.java:1242)
> at
> org.apache.calcite.rex.RexSimplify.simplifyAnd2ForUnknownAsFalse(RexSimplify.java:1109)
> at org.apache.calcite.rex.RexSimplify.simplifyAnds(RexSimplify.java:386)
> at
> org.apache.calcite.rex.RexSimplify.simplifyFilterPredicates(RexSimplify.java:2028)
> at org.apache.calcite.tools.RelBuilder.filter(RelBuilder.java:1048)
> at org.apache.calcite.tools.RelBuilder.filter(RelBuilder.java:1037)
> at
> org.apache.calcite.rel.rules.PushProjector.convertProject(PushProjector.java:382)
> at
> org.apache.calcite.rel.rules.ProjectFilterTransposeRule.onMatch(ProjectFilterTransposeRule.java:104)
> at
> org.apache.calcite.plan.volcano.VolcanoRuleCall.onMatch(VolcanoRuleCall.java:212)
> ... 41 more
> {noformat}
> When the query has any of the {{AND}} operands, or when
> {{ProjectFilterTransposeRule}} is not applied it is passed.
> Regarding the comparison of different data types, SQL spec says the following:
> {quote}8.2 <comparison predicate> Syntax Rules
> 3) The declared types of the corresponding fields of the two <row value
> predicand>s shall be comparable.
> {quote}
> But it also allows implicit casts from numeric types to chars (6.13 <cast
> specification>).
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