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https://issues.apache.org/jira/browse/CALCITE-2004?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16788114#comment-16788114
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Haisheng Yuan commented on CALCITE-2004:
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I opened a PR for this issue: https://github.com/apache/calcite/pull/1096
[~julianhyde] Can you take a look?
> The TableFunction left outer join was improperly translated
> -----------------------------------------------------------
>
> Key: CALCITE-2004
> URL: https://issues.apache.org/jira/browse/CALCITE-2004
> Project: Calcite
> Issue Type: Bug
> Reporter: Xingcan Cui
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Currently the TableFunction left outer join is translated to a
> {{LogicalCorrelate}} followed by a {{LogicalFilter}}. For instance, given a
> simple table {{WordCount(word:String, frequency:Int)}}, a table function
> {{split: word:String => (letter:String, length:String)}}, and a query
> {{SELECT word, letter, length FROM WordCount LEFT JOIN LATERAL
> TABLE(split(word)) AS T (letter, length) ON frequency = length OR length <
> 5"}} the query will be translated to the logical plan below.
> {code:java}
> LogicalProject(word=[$0], name=[$2], length=[$3])
> LogicalFilter(condition=[OR(=($1, CAST($3):BIGINT), <($3, 5))])
> LogicalCorrelate(correlation=[$cor0], joinType=[left],
> requiredColumns=[{0}])
> LogicalTableScan(table=[[WordCount]])
> LogicalTableFunctionScan(invocation=[split($cor0.word)],
> rowType=[RecordType(VARCHAR(65536) _1, INTEGER _2)], elementType=[class
> [Ljava.lang.Object;])
> {code}
> With this plan, an outer row might be completely filtered out (instead of
> being padded with null) if the join predicate filter filters out all join
> results produced by a correlate join for the outer row. Maybe we should
> attach the filter to the correlate operation.
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