Re: bitwise and/or aggregate functions?

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От Bruce Momjian
Тема Re: bitwise and/or aggregate functions?
Дата
Msg-id 200404271751.i3RHpQk15212@candle.pha.pa.us
обсуждение исходный текст
Ответ на bitwise and/or aggregate functions?  (Fabien COELHO <coelho@cri.ensmp.fr>)
Ответы Re: bitwise and/or aggregate functions?  (Fabien COELHO <coelho@cri.ensmp.fr>)
Список pgsql-hackers
Fabien COELHO wrote:
> 
> Dear hackers,
> 
> still in the spirit of "it may be useful to others, as it was to me, and
> it does cost very little", and before submitting a small patch and being
> exploded because it is obviously very stupid:
> 
> Would it be appropriate to contribute BIT_AND and BIT_OR aggregates
> for integer types, with some documentation and minimal validation?
> There has been a discussion recently on pgsql-general about that.
> 
> 1) mysql has them... it seems to be an argument here around sometimes;-)
>    it is in their proud list-of-features that it has and that postgresql
>    does not have.
> 
> 2) each declaration is a 4-line "CREATE AGGREGATE", the underlying
>    functions being already available for & and | operators.
> 
> 3) I know that one can add them if they are needed, but what
>    would be the point of NOT providing such simple features, and
>    having the basic user to have to learn about creating aggregate
>    functions and browse a long time in the documentation for that?
> 
> I needed them for some application: I'm happy I know how to add them now,
> but I would have been even happier if I had found them just available
> without having to learn about these intesting details about postgresql
> extensions.

I am confused why you would use bit on integers when there is a bit type
with an AND operator:
pg_catalog | &    | bit        | bit        | bit         | bitwise and

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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