Scott Marlowe wrote:
True. But that's only because it doesn't have a date to work against.
If you run:
select '2007-02-01 12:00:00'::timestamp + '1 month'::interval;
you get: 2007-03-01 12:00:00
If you run:
select '2007-03-01 12:00:00'::timestamp + '1 month'::interval;
you get: 2007-04-01 12:00:00
Then, if we run:
select ('2007-03-01 12:00:00'::timestamp + '1 month'::interval) -
'2007-03-01 12:00:00'::timestamp;
we get: 31 days
But if we run:
select ('2007-02-01 12:00:00'::timestamp + '1 month'::interval) -
'2007-02-01 12:00:00'::timestamp;
we get: 28 days
So, I'm not sure how many days a month has.
Try looking at a calendar.;-)
You will find that these are the exact days between the two dates. Feb
has 28 days, so 1st of feb plus 1 month puts you at 1st of march
march has 31 days so 1st of march plus 1 month puts you at 1st of april.
Try a leap year -
select ('2008-02-01 12:00:00'::timestamp + '1 month'::interval) -
'2008-02-01 12:00:00'::timestamp;
?column?
----------
29 days
(1 row)
--
Shane Ambler
pgSQL (at) Sheeky (dot) Biz
Get Sheeky @ http://Sheeky.Biz
