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

On Fri, Dec 26, 2008 at 03:34:33PM +0100, Ivan Sergio Borgonovo wrote:
> I noticed that starting from 8.2 the documentation at
> http://www.postgresql.org/docs/8.2/interactive/sql-expressions.html
> say that multiple distinct expressions are supported
>
> aggregate_name (DISTINCT expression [, expression] )

In 8.4, you'll be able to do:

WITH d AS (
    SELECT DISTINCT c1, c2 FROM table1
)
SELECT count(*) FROM d;

and very likely an OLAP version. :)

Cheers,
David.
>
> While previous docs just listed one:
>
> aggregate_name (DISTINCT expression)
>
> Still I'm using 8.3 and
>
> select count(distinct c1, c2) from table1;
>
> report:
>
> No function matches the given name and argument types. You might
> need to add explicit type casts.
>
> What should I write in spite of?
>
> select count(distinct c1, c2) from table1;
>
> --
> Ivan Sergio Borgonovo
> http://www.webthatworks.it
>
>
> --
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--
David Fetter <david@fetter.org> http://fetter.org/
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