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https://issues.apache.org/jira/browse/HIVE-15758?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16035656#comment-16035656
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Pengcheng Xiong commented on HIVE-15758:
----------------------------------------
Here is my 2 cents. I use a CTE to describe how i want to rewrite. The basic
idea is to give it a row number. In the first join, we use left join to keep
all the row_nums. In the second join, we are trying to match exactly the same
"row" as we want.
{code}
with part_rewrite as
(select *, ROW_NUMBER() over () as row_num from part)
select p1.p_size, p1.p_type from part_rewrite p1,
(select count(pp.p_size) as cnt, row_num from part_rewrite left outer join part
pp on part_rewrite.p_type <> pp.p_type group by row_num)p2
where p1.p_size<>p2.cnt and p1.row_num=p2.row_num;
{code}
Here are the rewrite test results:
{code}
horton=# select * from part;
p_size | p_type
--------+--------
1 | 1
1 |
1 | 2
1 | 3
2 | 3
2 | 32
233 | 2
| 2
|
| 3
233 | 2
(11 rows)
horton=# select * from part where p_size <> (select count(p_size) from part pp
where part.p_type <> pp.p_type);
p_size | p_type
--------+--------
1 | 1
1 |
1 | 2
1 | 3
2 | 3
2 | 32
233 | 2
233 | 2
(8 rows)
horton=# with part_rewrite as
horton-# (select *, ROW_NUMBER() over () as row_num from part)
horton-# select p1.p_size, p1.p_type from part_rewrite p1,
horton-# (select count(pp.p_size) as cnt, row_num from part_rewrite left outer
join part pp on part_rewrite.p_type <> pp.p_type group by row_num)p2
horton-# where p1.p_size<>p2.cnt and p1.row_num=p2.row_num;
p_size | p_type
--------+--------
1 | 1
1 |
1 | 2
1 | 3
2 | 3
2 | 32
233 | 2
233 | 2
(8 rows)
{code}
> Allow correlated scalar subqueries with aggregates which has non-equi join
> predicates
> -------------------------------------------------------------------------------------
>
> Key: HIVE-15758
> URL: https://issues.apache.org/jira/browse/HIVE-15758
> Project: Hive
> Issue Type: Sub-task
> Components: Logical Optimizer
> Reporter: Vineet Garg
> Assignee: Vineet Garg
> Labels: sub-query
>
> Queries such as
> {code} select * from part where p_size <> (select count(p_size) from part pp
> where part.p_type <> pp.p_type); {code} are currently not allowed since HIVE
> doesn't know how to rewrite such queries to preserve the correctness for
> cases when there is zero row
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