Uz.ytkownik Stephan Szabo napisa?:
> Does using X.group_id=3 in the where clause work better?
It works better, but not if you want to create a view and make
"select * from some_view where group_id=3" :-(
> 
> On 7.3 with no statistics for the table, that appears
> to move the filter into the subquery plan rather than the
> outer users scan.
Do you mean the second query will work on 7.3?
select
   group_id,
   user_id,
   a/sum_a as percent_a,
   b/sum_b as percent_b
from
   users U,
   (select
     sum(a) as sum_a,
     sum(b) as sum_b
    from users where group_id=U.group_id) X
where group_id=3;
Tomasz Myrta