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https://issues.apache.org/jira/browse/TAJO-2160?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15306175#comment-15306175
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ASF GitHub Bot commented on TAJO-2160:
--------------------------------------
Github user jinossy commented on a diff in the pull request:
https://github.com/apache/tajo/pull/1029#discussion_r65018556
--- Diff: tajo-core/src/main/proto/InternalTypes.proto ---
@@ -45,3 +45,8 @@ message CorrProto {
required double yvar = 5;
required double covar = 6;
}
+
+message StringAggProto {
+ required string value = 1;
--- End diff --
IMO, this proto is unnecessary define. the StringAgg is only to aggregate a
value.
What do you think about that?
> Implement string_agg function.
> ------------------------------
>
> Key: TAJO-2160
> URL: https://issues.apache.org/jira/browse/TAJO-2160
> Project: Tajo
> Issue Type: New Feature
> Components: Function/UDF
> Affects Versions: 0.11.3
> Reporter: Byunghwa Yun
> Priority: Minor
> Fix For: 0.12.0, 0.11.3
>
>
> I'll implement to concatenate the strings of a field within a group by query.
> I have a table:
> ID COMPANY_ID EMPLOYEE
> 1 1 Anna
> 2 1 Bill
> 3 2 Carol
> 4 2 Dave
> and I wanted to group by company_id to get something like:
> SELECT company_id, string_agg(employee, ', ')
> FROM mytable
> GROUP BY company_id;
> COMPANY_ID EMPLOYEE
> 1 Anna, Bill
> 2 Carol, Dave
> PostgreSQL supports string_agg function.
> http://www.postgresql.org/docs/current/static/functions-aggregate.html#FUNCTIONS-AGGREGATE-TABLE
> Thank you.
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