[
https://issues.apache.org/jira/browse/CALCITE-1753?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15968112#comment-15968112
]
MinJi Kim commented on CALCITE-1753:
------------------------------------
I agree with what you said, [~jni]. Do you have a suggestion as to how we
would we distinguish that for the operators? I suggested having another
preserveExprCondition to allow the user of the rule to specify which operations
they would want to push past outer joins, but that seems to be shifting the
work to the user vs. figuring it out automatically.
> ProjectJoinTransposeRule with preserveExprCondition pushes projects below
> outer-joins
> -------------------------------------------------------------------------------------
>
> Key: CALCITE-1753
> URL: https://issues.apache.org/jira/browse/CALCITE-1753
> Project: Calcite
> Issue Type: Bug
> Components: core
> Reporter: MinJi Kim
> Assignee: Julian Hyde
>
> I am pushing case statements past joins using ProjectJoinTransposeRule. For
> inner joins, the current behavior seems fine, but outer joins can lead to
> weird behavior, where the project is below the join and nulls can cause
> issues.
> {code}
> select
> count(*), case when t3.a3 is not null then t3.a3 else 100 end
> from
> t1 left outer join t3 on t1.c1 = t3.c3
> group by
> case when t3.a3 is not null then t3.a3 else 100 end
> order by
> case when t3.a3 is not null then t3.a3 else 100 end
> {code}
> Currently, ProjectJoinTransposeRule will push the case statement below the
> join as below. But, this case statement shouldn't be pushed. The query
> shouldn't return null but instead as 100 for any "unmatched" join condition
> since it is a left outer join with a case statement. But, the current plan
> would not prevent that.
>
> {code}
> LogicalProject with case statement
> LogicalJoin
> LogicalTableScan(table=[t1])
> LogicalTableScan(table=[t3])
> {code}
> {code}
> LogicalProject
> LogicalJoin
> LogicalProject with case statement
> LogicalTableScan(table=[t1])
> LogicalTableScan(table=[t3])
> {code}
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
