Re: Help with query involving aggregation and joining.

>
> ERROR:
> SELECT DISTINCT ON expressions must match
> initial ORDER BY expressions may be gotten over by
> wrapping the first query result in a subselect.
>
> not sure though if its proper.
> regds
> mallah.
>
> test=# SELECT * from ( SELECT distinct on (a.id) b.id
> ,courseid,name,submission from course a join history b on
> (a.id=b.courseid) ) as results order by results.submission desc;
>
I'm currently working with
select version();
version
---------------------------------------------------------------
PostgreSQL 7.2.3 on hppa-hp-hpux10.20, compiled by GCC 2.95.2
(1 row)
I've used your table definitions and sample data you've sent earlier
and do not receive an error message on the above SELECT statement.
Did you?

Regards, Christoph