I'm trying to create a summary log by hour. Here's the query (somewhat
simplified):

select to_char(mtrantime,'mm-dd hh AM') as datetime,
count(*) as tot from memtran
group by datetime
order by datetime;

The problem is this produces the data in the following order:

datetime | tot
-------------+-----
04-08 01 PM | 14
04-08 02 PM | 15
04-08 03 PM | 23
04-08 07 AM | 8
04-08 08 AM | 54
04-08 09 AM | 30
04-08 10 AM | 11
04-08 11 AM | 10
04-08 11 PM | 7
04-08 12 PM | 10

What I'd really like is to get it in chronological order by hour:

04-08 07 AM | 8
04-08 08 AM | 54
04-08 09 AM | 30
04-08 10 AM | 11
04-08 11 AM | 10
04-08 12 PM | 10
04-08 01 PM | 14
04-08 02 PM | 15
04-08 03 PM | 23
04-08 11 PM | 7

I would prefer not to show the time of day in 24 hour format, but
there doesn't appear to be a way to order by something that
isn't in the select and group by clause and I don't want to display
the hour twice.

Putting the AM/PM before the HH (which looks a bit clumsy) almost works,
except that 12PM gets sorted to the bottom after 11PM.

Is there an easy way around this?
--
Mike Nolan

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How about:

select to_char(mtrantime,'mm-dd hh AM') as datetime,
to_char(mtrantime,'AM') as sort_field,
count(*) as tot from memtran
group by sort_field, datetime
order by sort_field, datetime;

Then ignore the sort_field column?

Michael

"Mike Nolan" <nolan@gw.tssi.com> wrote in message
news:200404082349.i38NnN45017008@gw.tssi.com...[color=blue]
> I'm trying to create a summary log by hour. Here's the query (somewhat
> simplified):
>
> select to_char(mtrantime,'mm-dd hh AM') as datetime,
> count(*) as tot from memtran
> group by datetime
> order by datetime;
>
> The problem is this produces the data in the following order:
>
> datetime | tot
> -------------+-----
> 04-08 01 PM | 14
> 04-08 02 PM | 15
> 04-08 03 PM | 23
> 04-08 07 AM | 8
> 04-08 08 AM | 54
> 04-08 09 AM | 30
> 04-08 10 AM | 11
> 04-08 11 AM | 10
> 04-08 11 PM | 7
> 04-08 12 PM | 10
>
> What I'd really like is to get it in chronological order by hour:
>
> 04-08 07 AM | 8
> 04-08 08 AM | 54
> 04-08 09 AM | 30
> 04-08 10 AM | 11
> 04-08 11 AM | 10
> 04-08 12 PM | 10
> 04-08 01 PM | 14
> 04-08 02 PM | 15
> 04-08 03 PM | 23
> 04-08 11 PM | 7
>
> I would prefer not to show the time of day in 24 hour format, but
> there doesn't appear to be a way to order by something that
> isn't in the select and group by clause and I don't want to display
> the hour twice.
>
> Putting the AM/PM before the HH (which looks a bit clumsy) almost works,
> except that 12PM gets sorted to the bottom after 11PM.
>
> Is there an easy way around this?
> --
> Mike Nolan
>
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>[/color]

Mike Nolan <nolan@gw.tssi.com> writes:[color=blue]
> select to_char(mtrantime,'mm-dd hh AM') as datetime,
> count(*) as tot from memtran
> group by datetime
> order by datetime;
> The problem is this produces the data in the following order:
> ...
> What I'd really like is to get it in chronological order by hour:[/color]

You are grouping/ordering by the textual result of to_char(),
in which PM naturally follows AM. I think the behavior you
want would come from grouping/ordering by the underlying
timestamp column "mtrantime".

regards, tom lane

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> You are grouping/ordering by the textual result of to_char(),[color=blue]
> in which PM naturally follows AM. I think the behavior you
> want would come from grouping/ordering by the underlying
> timestamp column "mtrantime".[/color]

Well, I need it grouped by hour, but that led me to the solution:

select to_char(date_trunc('hour',mtrantime),'mm-dd hh AM') as
datetime, count(*) as tot, from memtran
group by mtranoper, date_trunc('hour',mtrantime)
order by mtranoper, date_trunc('hour',mtrantime)

I knew there had to be a straight-forward solution. Thanks Tom.
--
Mike Nolan

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> How about:[color=blue]
>
> select to_char(mtrantime,'mm-dd hh AM') as datetime,
> to_char(mtrantime,'AM') as sort_field,
> count(*) as tot from memtran
> group by sort_field, datetime
> order by sort_field, datetime;
>
> Then ignore the sort_field column?[/color]

I usually don't like to send managers reports with data labeled
'ignore this column'. :-)

With Tom's help, I found a solution.
--
Mike Nolan

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