Of course, right when I hit send I thought of another option that makes the SQL a little less readable but perhaps gets rid of the ambiguity. Using ordinals in the GROUP BY:
SELECT path[1], path[2], path[3], path[4], sum(value)
FROM bind_group_by
GROUP BY GROUPING SETS (
(1, 2, 3, 4),
(1, 2, 3),
(1, 2),
(1),
()
)
ORDER BY 1, 2, 3, 4;
Since I'm generating the SQL I'm not too worried about the readability and it works with bind variables too. I promise I'll stop thinking after this one ;-)
Thanks!
- Aner
Aner Perez <aner.perez+pgsql-general@gmail.com> writes:
> Or if using indexed path elements in the GROUP BY is the issue and I should
> put the array indexing in a subselect and do the aggregation in the outer
> select. Like this:
> -- Safer Subselect Version --
> SELECT level1, level2, level3, level4, sum(value)
> FROM (
> SELECT path[1] as level1, path[2] as level2, path[3] as level3, path[4]
> as level4, value
> FROM bind_group_by
> ) AS expanded
> GROUP BY GROUPING SETS (
> (level1, level2, level3, level4),
> (level1, level2, level3),
> (level1, level2),
> (level1),
> ()
> )
> ORDER BY 1, 2, 3, 4;
Yeah, that one looks a lot safer from here. There's no question about
which expressions are supposed to match what. It should end up with
the same plan, too.
regards, tom lane