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Re: FILTER clause for non-aggregate window functions - Mailing list pgsql-sql

From Андрей Жиденков
Subject Re: FILTER clause for non-aggregate window functions
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Msg-id CAN=gQ4Aa5i16eWC_UgsPswpMBsVy6Pshvmq76E=Y4gk98OLg8A@mail.gmail.com
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In response to Re: FILTER clause for non-aggregate window functions  (Tom Lane <tgl@sss.pgh.pa.us>)
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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@sss.pgh.pa.us> wrote:
\xC1\xBA\xFFАндрей Жидем\xAF\xFDков <pensnarik@gmail.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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