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https://issues.apache.org/jira/browse/CALCITE-7826?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Julian Hyde reassigned CALCITE-7826:
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Assignee: Julian Hyde
> IS NOT DISTINCT FROM gives wrong result in Enumerable convention when applied
> to DECIMAL values of different scales
> -------------------------------------------------------------------------------------------------------------------
>
> Key: CALCITE-7826
> URL: https://issues.apache.org/jira/browse/CALCITE-7826
> Project: Calcite
> Issue Type: Bug
> Reporter: Julian Hyde
> Assignee: Julian Hyde
> Priority: Major
>
> IS NOT DISTINCT FROM compares DECIMAL values using equals, so values with
> different scales are distinct.
> In the Enumerable convention, {{IS NOT DISTINCT FROM}} and {{IS DISTINCT
> FROM}} are implemented by {{{}RexImpTable.DistinctFromImplementor{}}}, which
> compares non-null operands using {{{}Objects.equals{}}}, and does not
> harmonize the operand types (`harmonize` is `false`). For
> {{{}java.math.BigDecimal{}}}, {{equals}} is sensitive to scale, so 1.10 and
> 1.1 are distinct values. SQL's {{=}} operator compares the same values
> numerically, and finds them equal. So for non-null {{DECIMAL}} operands, {{x
> IS NOT DISTINCT FROM y}} and {{x = y}} can disagree.
> A query parsed from SQL is not affected.
> {{StandardConvertletTable.convertIsDistinctFrom}} expands {{IS [NOT] DISTINCT
> FROM}} using {{{}RelOptUtil.isDistinctFrom{}}}, so the plan uses {{IS NULL}}
> and {{=}} on operands that have been cast to a common type; for example, {{a
> IS NOT DISTINCT FROM b}} where {{a}} is {{DECIMAL(3, 2)}} and {{b}} is
> {{DECIMAL(2, 1)}} becomes {{OR(AND(IS NULL(a), IS NULL(b)), IS TRUE(=(a,
> CAST(b):DECIMAL(3, 2))))}}The {{IS_NOT_DISTINCT_FROM}} operator reaches
> {{DistinctFromImplementor}} only if a plan calls it directly, for example
> using {{{}RelBuilder.call(SqlStdOperatorTable.IS_NOT_DISTINCT_FROM, a, b){}}}.
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