Re: Order by YYYY MM DD in reverse chrono order trouble

> Hello,
>
> I am trying to select distinct dates and order them in the reverse
> chronological order.  Although the column type is TIMESTAMP, in this
> case I want only YYYY, MM, and DD back.
>
> I am using the following query, but it's not returning dates back in
> the reverse chronological order:
>
> SELECT DISTINCT
>   date_part('year', uu.add_date),  date_part('month', uu.add_date),
>   date_part('day', uu.add_date)
>
> FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
> ui.id=uu.user_id
> WHERE uus.x_id=1
>
> ORDER BY
> date_part('year', uu.add_date), date_part('month', uu.add_date),
> date_part('day',  uu.add_date) DESC;
>
>
> This is what the above query returns:
>
>  date_part | date_part | date_part
> -----------+-----------+-----------
>       2004 |         2 |         6
>       2004 |         4 |        20
> (2 rows)
>
>
> I am trying to get back something like this:
> 2004 4 20
> 2004 4 19
> 2004 2 6
> ...
>
> My query is obviously wrong, but I can't see the mistake.  I was
> wondering if anyone else can see it.  Just changing DESC to ASC, did
> not work.
>
> Thank you!
> Otis
What you could try to do in your order by clause is the following:
ORDER BY
date_part('year', uu.add_date) DESC,
date_part('month', uu.add_date) DESC,
date_part('day',  uu.add_date) DESC;
That way you are sure each of the fields is sorted DESC. if you don't specify a direction in your order by clause
postgreswill take ASC as the default. I think that he does "ASC,ASC,DESC" instead. I'm not sure if he applies the DESC
toall specified fields in the order by if you declare it only once. 


Regards,

Stijn Vanroye