From: | Андрей Жиденков <pensnarik(at)gmail(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-sql(at)lists(dot)postgresql(dot)org |
Subject: | Re: FILTER clause for non-aggregate window functions |
Date: | 2017-12-12 16:53:01 |
Message-ID: | CAN=gQ4Aa5i16eWC_UgsPswpMBsVy6Pshvmq76E=Y4gk98OLg8A@mail.gmail.com |
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Lists: | pgsql-sql |
I could not put the restrictions in WHERE because I want them to be applied
only to the window frame, not to all selected rows.
On 12 Dec. 2017 18:35, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> =?UTF-8?B?0JDQvdC00YDQtdC5INCW0LjQtNC10L3QutC+0LI=?= <pensnarik(at)gmail(dot)com>
> writes:
> > Why FILTER is not implemented for non-aggregate functions?
>
> The SQL standard only describes FILTER for aggregates. I'm not sure
> offhand whether it'd be semantically sensible for window functions.
> In any case, seems like most of the cases where you'd want it can be
> expressed equally well by putting the restriction into WHERE.
>
> regards, tom lane
>
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