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From Paul Rogers <par0...@yahoo.com.INVALID>
Subject Re: Regarding EXCEPT clause of drill
Date Thu, 16 Jan 2020 18:57:00 GMT
Thanks Arina.

I believe that EXCEPT is set subtraction A - B. Drill does (I believe) already support UNION
distinct, which is set union (A U B). If so, it would be a nice little project for someone
to implement EXCEPT by reversing the polarity of comparison: discard the non-dups rather than
the dups. I'm sure it is a bit harder than that, but still would be a good project for someone
who want to get experience with query engine internals.

- Paul


    On Thursday, January 16, 2020, 04:16:49 AM PST, Arina Yelchiyeva <arina.yelchiyeva@gmail.com>
 Paul is right, Drill does not support Except syntax.
In this Jira in comments you can find ways how to rewrite the query to achieve the same result:
https://issues.apache.org/jira/browse/DRILL-4232 <https://issues.apache.org/jira/browse/DRILL-4232>

Kind regards,

> On Jan 16, 2020, at 1:09 AM, Paul Rogers <par0328@yahoo.com.INVALID> wrote:
> Hi Itisha,
> Welcome to the Drill user mail list!
> For those readers (like me) who are not familiar with the keyword, EXCEPT works like
UNION to join to SELECT statements: SELECT ... EXCEPT SELECT ... See [1]. Seems pretty useful.
> A quick check of our parser source code suggests that Drill does not support the EXCEPT
syntax. Drill does not even treat EXCEPT as a keyword.
> Please file a JIRA ticket to request this feature.
> Thanks,
> - Paul
> [1] https://www.tutorialspoint.com/sql/sql-except-clause.htm
>    On Wednesday, January 15, 2020, 12:50:36 AM PST, itisha Gupta <itishagupta.2396@gmail.com>
> Hey team,
> I am trying to use EXCEPT operator of Apache drill but it's not working.
> Does Apache drill supports EXCEPT?
> Regards,
> Itisha
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