Re: get first and last row in one sql as two columns

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От Rob Sargent
Тема Re: get first and last row in one sql as two columns
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Msg-id 55E78685.3020701@gmail.com
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Ответ на get first and last row in one sql as two columns  (Tom Smith <tomsmith1989sk@gmail.com>)
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On 09/02/2015 05:14 PM, Tom Smith wrote:
Hi:

I need to get the first and last tow in one sql like below

select first(col1), last(col1) from table order by col1

I saw some posting in wiki with a custom function (or C extention)
to do this.   Is it widely used and reliable?
https://wiki.postgresql.org/wiki/First/last_(aggregate)

I am wondering why these two functions are not part of postgresql built-in
functions as it has many use cases

Thanks
But what I think you are looking for are the windowing functions as what you propose breaks down pretty quickly with more complicated queries.

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