On 2006-01-24, Will Glynn <wglynn@freedomhealthcare.org> wrote:
> You might try:
>
> SELECT some_column
> FROM some_table
> GROUP BY some_column
> HAVING SUM(CASE WHEN sort_order=1 THEN 1 ELSE 0 END) = 0;
SELECT some_column
FROM some_table
GROUP BY some_column
HAVING every(sort_order <> 1);
every() is in 8.1 at least (can't recall when it was introduced); it's the
same as bool_and(), i.e. an aggregate that returns true only if all inputs
are true. Why isn't there a corresponding any(), I wonder? (bool_or does
exist)
It should be possible to define bool_and() or every() in the usual way as
a custom aggregate even on versions that don't have them builtin.
--
Andrew, Supernews
http://www.supernews.com - individual and corporate NNTP services
