Xingcan Cui created CALCITE-2004:
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Summary: 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
Assignee: Julian Hyde
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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