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From Julian Hyde <jh...@apache.org>
Subject Re: Distinct aggregates
Date Wed, 05 Apr 2017 22:05:16 GMT
Yes… but then what? We need at least one implementation that can calculate distinct over
windows, and we don’t have one currently.

So, first level of ambition: throw an error, saying “We don’t support windowed distinct
aggregates”. Second level of ambition, implement them and remove the error.

Thanks for logging https://issues.apache.org/jira/browse/CALCITE-1740 <https://issues.apache.org/jira/browse/CALCITE-1740>.
Let’s have any further discussion there. Contributions welcome, of course.

Julian


> On Apr 5, 2017, at 12:51 AM, Radu Tudoran <radu.tudoran@huawei.com> wrote:
> 
> Hi,
> 
> Wouldn't it be possible rather than throwing an error to set the flag instead?
> 
> Best regards,
> 
> Dr. Radu Tudoran
> Senior Research Engineer - Big Data Expert
> IT R&D Division
> 
> 
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> 
> -----Original Message-----
> From: Julian Hyde [mailto:jhyde@apache.org] 
> Sent: Tuesday, April 04, 2017 11:09 PM
> To: dev@calcite.apache.org
> Subject: Re: Distinct aggregates
> 
> Calcite doesn’t currently support distinct aggregates in window functions. See https://issues.apache.org/jira/browse/CALCITE-476
<https://issues.apache.org/jira/browse/CALCITE-476>. 
> 
> That said, it shouldn’t silently swallow the DISTINCT keyword. It should give an error.
I suspect that some rule is ignoring the distinct flag. Can you log a JIRA case please?
> 
> Julian
> 
> 
>> On Apr 4, 2017, at 9:46 AM, Radu Tudoran <radu.tudoran@huawei.com> wrote:
>> 
>> Hi,
>> 
>> I am trying to parse the logical query plan that results after executing queries
such as:
>> 
>> SELECT B1, SUM(DISTINCT B2) OVER  (ORDER BY  B4 RANGE BETWEEN INTERVAL '10' SECOND
PRECEDING AND CURRENT ROW) FROM T
>> 
>> However, when I look in the list of the aggregates from the LogicalWindow, the Aggregate
does not have any marker of being distinct. I also checked the isDistinct() and it returns
false for the aggregate.
>> 
>> .. I get as LogicalWindow object
>> LogicalWindow(window#0=[window(partition {} order by [2] range between $3 PRECEDING
and CURRENT ROW aggs [COUNT($1), $SUM0($1)])])
>> 
>> Moreover if I run a query that has a count and a count distinct over a window it
will be simplified to a single count aggregate.
>> 
>> Am I missing something or is there a bug?
>> 
>> Best regards,
>> 
>> Radu
>> 
> 


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