Thread

Re: [HACKERS] SELECT DISTINCT question

Hannu Krosing <hannu@trust.ee> — 1999-07-13T20:50:57Z

Oleg Bartunov wrote:
> 
> I got a problem with query:
> 
> select distinct (date), bytes  from access_log;
> 
> which works but not as I expect. I thought this query will select
> all rows with distinct values of 'date' column, but it get
> distinct pairs 'date, bytes' . From documnetation I see
> 
> "DISTINCT will eliminate all duplicate rows from the selection.
> DISTINCT ON column will eliminate all duplicates in the specified column;
> this is equivalent to using GROUP BY column.

If it is equivalent to GROUP BY then it should allow only aggregates 
in non-distinct columns, like:

select distinct on date date, sum(bytes) from access_log;

If it does not, then it should be files as a bug imho.

-----------------
Hannu