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From Jeff Hammerbacher <>
Subject Re: Running and Sliding on Aggregates
Date Wed, 17 Nov 2010 01:02:59 GMT
Hey Michael,

I unfortunately can't tell you how to get around this limitation, but I can
point you to the JIRA issue that attempts to capture the requirements: If you could describe your
use case there, we can capture it for posterity in hope that some future
Hive engineer will find time to crank out a patch.


On Tue, Nov 16, 2010 at 12:49 PM, Michael Roessler <> wrote:

> I suffer from "sql-itis", especially the SQL:2003 variant. I can barely get
> a data-related programming line out of my fingers that doesn't include a
> "partition by" or an "over order by".
> Many of the data sets I analyze can be simplified for comprehension by
> thinking of them as having only three columns: a descriptive columns
> (ENTITY_NAME), a date column (20101611), and a numeric or double value
> column (456.789). A time series. Much of what I do is partition the
> descriptive column, order by the date column, and apply a moving aggregate
> (like average) over a sliding window of the value column.
> Example:
> select entity_name, value_date, avg(value) over (partition by entity_name
> order by value_date rows between 20 preceding and current row) as
> twenty_period_moving_average
> from table_with_a_billion_rows
> I am aware that HQL does not currently include this type of SQL analytic
> function. What are my options, if any, to accomplish the above with Hive?
> I'm looking at UDAF, but I haven't yet grokked.
> Thanks,
> Michael
> Michael Roessler, CFA

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