Re: count (DISTINCT expression [ , ... ] ) and documentation

2008/12/26 Ivan Sergio Borgonovo <mail(at)webthatworks(dot)it>:
> On Fri, 26 Dec 2008 16:23:52 +0100
> "Pavel Stehule" <pavel(dot)stehule(at)gmail(dot)com> wrote:
>
>> 2008/12/26 Ivan Sergio Borgonovo <mail(at)webthatworks(dot)it>:
>> > On Fri, 26 Dec 2008 15:46:48 +0100
>> > "Pavel Stehule" <pavel(dot)stehule(at)gmail(dot)com> wrote:
>> >
>> >> count has only one argument,
>> >
>> > then what was changed between 8.1 and 8.2 to change the docs?
>> > None of the functions listed in:
>> > http://www.postgresql.org/docs/8.2/static/functions-aggregate.html
>> > seems to support
>> > aggregate(distinct exp [,exp])
>>
>> http://www.postgresql.org/docs/8.2/interactive/functions-aggregate.html
>>
>> http://www.postgresql.org/docs/8.2/interactive/functions-aggregate.html#FUNCTIONS-AGGREGATE-STATISTICS-TABLE
>
>
> yeah but no function seems to support
>
> aggregate(distinct x, y)
>
>> CREATE AGGREGATE name ( input_data_type [ , ... ] ) (
>> SFUNC = sfunc,
>> STYPE = state_data_type
>> [ , FINALFUNC = ffunc ]
>> [ , INITCOND = initial_condition ]
>> [ , SORTOP = sort_operator ]
>> )
>
>
> OK... but how am I going to implement an user defined aggregate that
> support without resorting to C?
>
> myaggfunc(distinct x, y)?
>
> Otherwise to what is it referring
>
> http://www.postgresql.org/docs/8.2/interactive/sql-expressions.html
>
> aggregate_name (DISTINCT expression [ , ... ] )
>

ok, I tested and it isn't supported yet. This is documentation bug.
DISTINCT is allowed only for single argument aggregate.

Regards
Pavel Stehule

> --
> Ivan Sergio Borgonovo
> http://www.webthatworks.it
>
>
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