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https://issues.apache.org/jira/browse/FLINK-5256?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15761740#comment-15761740
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Fabian Hueske commented on FLINK-5256:
--------------------------------------
Sure, the plan I got was the logical plan before optimization (hence the
logical operator and not the DataSet operators).
It seems that the change of FLINK-5255 was sufficient to execute the query that
I posted before. The optimizer seems to have converted the left join into a
regular inner join.
The goal of this issue is to support outer joins with {{DataSetSingleRowJoin}}
in order to execute a query like the following:
{code}
SELECT b
FROM t1
LEFT JOIN
(SELECT COUNT(*) AS cnt FROM t2) AS x
ON a < cnt
{code}
So we need an outer join with a non-equality predicate and one input being a
global aggregation (single row input).
> Extend DataSetSingleRowJoin to support Left and Right joins
> -----------------------------------------------------------
>
> Key: FLINK-5256
> URL: https://issues.apache.org/jira/browse/FLINK-5256
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Affects Versions: 1.2.0
> Reporter: Fabian Hueske
>
> The {{DataSetSingleRowJoin}} is a broadcast-map join that supports arbitrary
> inner joins where one input is a single row.
> I found that Calcite translates certain subqueries into non-equi left and
> right joins with single input. These cases can be handled if the
> {{DataSetSingleRowJoin}} is extended to support outer joins on the
> non-single-row input, i.e., left joins if the right side is single input and
> vice versa.
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