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https://issues.apache.org/jira/browse/DRILL-6963?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16747905#comment-16747905
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benj commented on DRILL-6963:
-----------------------------
Sure, for example, PostgreSQL has these kind of functionality
* Work with array : [https://www.postgresql.org/docs/11/arrays.html]
* Aggregate in array => array_agg(exp) :
[https://www.postgresql.org/docs/11/functions-aggregate.html]
* Some array function and operators :
[https://www.postgresql.org/docs/9.1/functions-array.html]
* Some other functions like :
** {{regexp_split_to_array}}(text, pattern, flags) :
[https://www.postgresql.org/docs/current/functions-string.html]
array_agg() is useful, particularly when you group by an item and would like to
keep some information from another that has variable length / number of line
concerned in the original table is different for each group.
Example :
{code:java}
With table records
alice;1
alice;2
bob;1
bob;2
bob;3
charles;5
SELECT firstname, array_agg(DISTINCT score ORDER BY score) AS dist_scores
FROM records
GROUP BY firstname;
firstname | dist_score
--------- | ----------
alice | {1,2}
bob | {1,2,3}
charles | {5}
{code}
> create/aggregate/work with array
> --------------------------------
>
> Key: DRILL-6963
> URL: https://issues.apache.org/jira/browse/DRILL-6963
> Project: Apache Drill
> Issue Type: Wish
> Components: Functions - Drill
> Reporter: benj
> Priority: Major
>
> * Add the possibility to build array (like : SELECT array[a1,a2,a3...]) -
> ideally work with all types
> * Add a default array_agg (like : SELECT col1, array_agg(col2),
> array_agg(DISTINCT col2) FROM ... GROUP BY col1) ; - ideally work with all
> types
> * Add function/facilities/operator to work with array
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