Re: sorting by day of the week

Nevermind, I figured out that I just needed to do it like this:

SELECT to_char( logtime, 'Dy'),count(*),to_char( logtime, 'D') FROM
sclog WHERE date_trunc('day', logtime) > current_date + '7 day
ago'::interval group by to_char( logtime, 'Dy'),to_char( logtime, 'D')
ORDER BY to_char( logtime, 'D') DESC;

It is interesting that I can't put to_char( logtime, 'D') in the the
group by without putting it in the select.

Joseph Shraibman wrote:
> p8:owl=>SELECT to_char( logtime, 'Dy'),count(*) FROM logtab WHERE
> date_trunc('day', logtime) > current_date + '7 day ago'::interval group
> by to_char( logtime, 'Dy') ORDER BY to_char( logtime, 'Dy') DESC;
> to_char | count
> ---------+-------
> Wed | 1447
> Tue | 618
> Thu | 1161
> Sun | 230
> Sat | 362
> Mon | 760
> Fri | 1281
> (7 rows)
>
> The problem is that I want those results sorted in day of week order,
> not text order of the day name, so I tried this:
>
> p8:owl=>SELECT to_char( logtime, 'Dy'),count(*) FROM sclog WHERE
> date_trunc('day', logtime) > current_date + '7 day ago'::interval group
> by to_char( logtime, 'Dy') ORDER BY to_char( logtime, 'D') DESC;
> ERROR: column "sclog.logtime" must appear in the GROUP BY clause or be
> used in an aggregate function
>
> Now obviously I don't want to group by logtime (a timestamp) so how do I
> work around this? What I really need is a function that converts from
> the char representation to a day of week number or vice versa. I also
> have the same problem with month names.