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From "Yin Huai (JIRA)" <>
Subject [jira] [Commented] (SPARK-9740) first/last aggregate NULL behavior
Date Tue, 11 Aug 2015 20:43:46 GMT


Yin Huai commented on SPARK-9740:

Thanks. I will change the behavior to respecting nulls.

> first/last aggregate NULL behavior
> ----------------------------------
>                 Key: SPARK-9740
>                 URL:
>             Project: Spark
>          Issue Type: Sub-task
>          Components: SQL
>            Reporter: Herman van Hovell
>            Assignee: Yin Huai
> The FIRST/LAST aggregates implemented as part of the new UDAF interface, return the first
or last non-null value (if any) found. This is a departure from the behavior of the old FIRST/LAST
aggregates and from the FIRST_VALUE/LAST_VALUE aggregates in Hive. These would return a null
value, if that happened to be the first/last value seen. SPARK-9592 tries to 'fix' this behavior
for the old UDAF interface.
> Hive makes this behavior configurable, by adding a skipNulls flag. I would suggest to
do the same, and make the default behavior compatible with Hive.

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