On 06/27/2011 10:49 AM, David E. Wheeler wrote:
Hackers,
I'm curious about behavior such as this:
bric=# select generate_series('2011-05-31'::timestamp ,
'2012-04-01'::timestamp, '1 month');
generate_series
---------------------
2011-05-31 00:00:00
2011-06-30 00:00:00
2011-07-30 00:00:00
2011-08-30 00:00:00
2011-09-30 00:00:00
2011-10-30 00:00:00
2011-11-30 00:00:00
2011-12-30 00:00:00
2012-01-30 00:00:00
2012-02-29 00:00:00
2012-03-29 00:00:00
It seems to me that this is subject to interpretation. If I was building a
calendaring app, for example, I might rather that the results were:
generate_series
---------------------
2011-05-31 00:00:00
2011-06-30 00:00:00
2011-07-31 00:00:00
2011-08-31 00:00:00
2011-09-30 00:00:00
2011-10-31 00:00:00
2011-11-30 00:00:00
2011-12-31 00:00:00
2012-01-31 00:00:00
2012-02-29 00:00:00
2012-03-31 00:00:00
Is there some way to change the interpretation of interval calculation like
this? Or would I just have to write my own function to do it the way I want?
Thanks,
David
That's just how intervals that represent varying periods of time work.
You would need to write your own. But a series of end-of-month dates is
pretty easy:
select generate_series('2011-06-01'::timestamp ,
'2012-04-01'::timestamp, '1 month') - '1 day'::interval;
?column?
---------------------
2011-05-31 00:00:00
2011-06-30 00:00:00
2011-07-31 00:00:00
2011-08-31 00:00:00
2011-09-30 00:00:00
2011-10-31 00:00:00
2011-11-30 00:00:00
2011-12-31 00:00:00
2012-01-31 00:00:00
2012-02-29 00:00:00
2012-03-31 00:00:00
Cheers,
Steve
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