| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | pgsql-hackers(at)postgreSQL(dot)org, Hitoshi Harada <umi(dot)tanuki(at)gmail(dot)com> |
| Subject: | Re: Frames vs partitions: is SQL2008 completely insane? |
| Date: | 2008-12-26 21:41:01 |
| Message-ID: | 15681.1230327661@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
I wrote:
> Lastly, for a simple aggregate used with an OVER clause, the current
> patch seems to define the aggregate as being taken over the frame
> rather than the partition, but I cannot find anything in SQL2008 that
> lends any support to *either* definition.
Never mind that --- I found it in 10.9 syntax rule 4.b.
But what this seems to boil down to is that LEAD() and LAST_VALUE()
are completely useless unless you're allowed to specify a nondefault
framing clause ... and don't mind ignoring the clearly-insane
restriction of 6.10 syntax rule 6.b.
The minimum extra functionality needed to make these functions useful
would seem to be to allow UNBOUNDED FOLLOWING ...
regards, tom lane
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