Re: Hourly dates

Thanks for this, I can easily determine the number of records I want.

Andrew

On Tue, Jun 23, 2009 at 10:52 AM, Steve
Crawford<scrawford(at)pinpointresearch(dot)com> wrote:
> Andrew Maclean wrote:
>>
>> Is this the best way of getting a table of hourly dates?
>>
>> -- How to generate a table of dates at hourly intervals between two dates.
>>
>> -- select timestamp 'epoch' + generate_series * interval '1 second' as
>> dates from generate_series(extract(epoch from date_trunc('hour',
>> timestamp '2001-02-16 20:38:40'))::bigint,extract(epoch from
>> date_trunc('hour', timestamp '2001-02-17 20:38:40'))::bigint, 3600)
>> select generate_series * interval '1 second' +  date_trunc('hour',
>> timestamp '2001-02-16 20:38:40') as dates
>>  from generate_series(0,extract(epoch from(date_trunc('hour',
>> timestamp '2001-02-17 20:38:40') - date_trunc('hour', timestamp
>> '2001-02-16 20:38:40')))::bigint, 3600)
>>
>> The commented out query seems to take into account the timezone which
>> is not what I want.
>>
>> Andrew
>>
>>
>>
>
> Depends on what you have available as input. If you know the starting time
> and number of records it's pretty easy:
>
> Without time-zone:
> select '2009-03-05 0100'::timestamp + generate_series(0,100) * '1
> hour'::interval;
> ...
> 2009-03-07 23:00:00
> 2009-03-08 00:00:00
> 2009-03-08 01:00:00
> 2009-03-08 02:00:00
> 2009-03-08 03:00:00
> 2009-03-08 04:00:00
> ...
>
>
> With time-zone info:
> select '2009-03-05 0100'::timestamptz + generate_series(0,100) * '1
> hour'::interval;
> ...
> 2009-03-07 23:00:00-08
> 2009-03-08 00:00:00-08
> 2009-03-08 01:00:00-08
> 2009-03-08 03:00:00-07
> 2009-03-08 04:00:00-07
> 2009-03-08 05:00:00-07
> 2009-03-08 06:00:00-07
> ...
>
> Cheers,
> Steve
>
>
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--
___________________________________________
Andrew J. P. Maclean
Centre for Autonomous Systems
The Rose Street Building J04
The University of Sydney 2006 NSW
AUSTRALIA
Ph: +61 2 9351 3283
Fax: +61 2 9351 7474
URL: http://www.acfr.usyd.edu.au/
___________________________________________