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https://issues.apache.org/jira/browse/CALCITE-4805?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17420395#comment-17420395
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duan xiong commented on CALCITE-4805:
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[~julianhyde] HI. Sorry, I don't describe it clearly. When I find when The IN
sub-query can't be converted to OR when the value list contains Null. And
According to understanding， The condition can handle 3-Valued Logic very well.
I don't find any other reasons don't convert It.
If as you mentioned above, this line was added to fix a bug, Then we need a
unit test to protect it. (Before the PR, I have searched the related ISSUE, And
I don't find the reason). So I think this is an improvement.
> The IN sub-query can't be converted to OR when value list contains Null.
> ------------------------------------------------------------------------
>
> Key: CALCITE-4805
> URL: https://issues.apache.org/jira/browse/CALCITE-4805
> Project: Calcite
> Issue Type: Bug
> Reporter: duan xiong
> Assignee: duan xiong
> Priority: Major
>
> for example:
> {code:java}
> select * from emp where deptno in (null,2){code}
> Now the RelNode is:
> {code:java}
> LogicalProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4],
> SAL=[$5], COMM=[$6], DEPTNO=[$7], SLACKER=[$8])
> LogicalJoin(condition=[=($7, $9)], joinType=[inner])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> LogicalAggregate(group=[{0}])
> LogicalValues(tuples=[[{ null }, { 2 }]]){code}
> The RelNode should be:
> {code:java}
> LogicalProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4],
> SAL=[$5], COMM=[$6], DEPTNO=[$7], SLACKER=[$8])
> LogicalFilter(condition=[OR(=($7, null), =($7, 2))])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]]){code}
> So I think when the sub-query value list size is under the
> threshold(IN_SUB_QUERY_THRESHOLD), they can be converted to OR(no matter have
> the NullLiteral or not).
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