Re: Help with query involving aggregation and joining.

sorry i did not post any sample data or definations.
i was replying to someone else's posting

i do get such an error on pgsql 7.3.2

regds
mallah.

>>
>> 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

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