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https://issues.apache.org/jira/browse/CALCITE-6741?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17907250#comment-17907250
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xiong duan edited comment on CALCITE-6741 at 12/20/24 1:12 AM:
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I get it. We add the condition when unknownAsUnknow and unknowAsFalse. We need
to know the value $0 if we think unknown as true. (This is on the premise that
$0 is non-nullable)
was (Author: nobigo):
I get it. We add the condition when unknownAsUnknow and unknowAsFalse. We need
to know the value $0 if we think unknown as true.
> Incorrect type inference in AbstractTypeCoercion.commonTypeForBinaryComparison
> ------------------------------------------------------------------------------
>
> Key: CALCITE-6741
> URL: https://issues.apache.org/jira/browse/CALCITE-6741
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.38.0
> Reporter: Mihai Budiu
> Assignee: Mihai Budiu
> Priority: Minor
>
> This function converts an expression into another expression which does not
> have the same type.
> The function convertInToOr has the following JavaDoc:
> {code:java}
> /* Converts "x IN (1, 2, ...)" to "x=1 OR x=2 OR ..." */
> {code}
> This is unsound when x is not nullable and the list contains NULL.
> The "in" expression can never evaluate to NULL in that case, whereas the
> converted expression can.
> As an example, consider this test case, which is a simplified version of a
> test from Sql Logic Test:
> {code:sql}
> SELECT CASE WHEN 1 NOT IN ( NULL, COUNT(*) ) THEN 1 END
> {code}
> The plan produced for this query is as follows:
> {code}
> LogicalProject(EXPR$0=[CASE(CAST(AND(null, <>(1, $0))):BOOLEAN NOT NULL,
> 1, null:INTEGER)]), id = 202
> LogicalAggregate(group=[{}], agg#0=[COUNT()]), id = 200
> LogicalValues(tuples=[[{ 0 }]]), id = 160
> {code}
> Notice that there's a CAST(AND ...): BOOLEAN NOT NULL. Unfortunately the AND
> expression as written is nullable, so this cast is unsound.
> I am thinking that the correct expansion should use IS_NOT_DISTINCT_FROM
> instead of EQUALS.
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