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https://issues.apache.org/jira/browse/IMPALA-10920?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17416560#comment-17416560
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Gabor Kaszab commented on IMPALA-10920:
---------------------------------------
Just for the record, there is an ongoing discussion about the final syntax and
the code design on the dev@ mail list:
[https://mail-archives.apache.org/mod_mbox/impala-dev/202109.mbox/thread]
Will post the final conclusion here once we get there.
> UNNEST function for arrays in the select list
> ---------------------------------------------
>
> Key: IMPALA-10920
> URL: https://issues.apache.org/jira/browse/IMPALA-10920
> Project: IMPALA
> Issue Type: New Feature
> Components: Backend, Frontend
> Reporter: Gabor Kaszab
> Assignee: Gabor Kaszab
> Priority: Major
> Labels: complextype
>
> There is a need for implementing an UNNEST(array) function that could be
> given in the select list so that we can replicate Postgres functionality that
> has the very same.
> Considering the following table:
> {code:java}
> CREATE TABLE tbl (
> id int,
> arr1 array<int>,
> arr2 array<int>)
> STORED AS PARQUET;
> {code}
> with this data:
> {code:java}
> 1, {1,2}, {11,22,33}
> {code}
> A sample query would look like this:
> {code:java}
> SELECT id, UNNEST(arr1), UNNEST(arr2) FROM tbl;
> {code}
> ||id||unnest(arr1)||unnest(arr2)||
> |1|1|11|
> |1|2|22|
> |1|null|33|
> Not that the expected is to 'zip' the arrays instead of joining their values
> to have the same behaviour as Postgres 10+.
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