Re: current_date / datetime stuff

Kristo Kaiv escreveu:
> oneliner:
> 
> select date_trunc('month',now()) + ((8 - extract('dow' from 
> date_trunc('month',now()))||'days')::text)::interval;
> 



There is a problem when first monday is 1st or 2nd day of month.

bdteste=# SELECT date_trunc('month',meses) + ((8 - extract('dow' from 
date_trunc ('month',meses))||'days')::text)::interval FROM (SELECT 
('2007-' || s.a || '-15')::timestamp as meses FROM generate_series(1,12) 
as s(a)) AS foo;      ?column?
--------------------- 2007-01-08 00:00:00 2007-02-05 00:00:00 2007-03-05 00:00:00 2007-04-09 00:00:00 2007-05-07
00:00:002007-06-04 00:00:00 2007-07-09 00:00:00 2007-08-06 00:00:00 2007-09-03 00:00:00 2007-10-08 00:00:00 2007-11-05
00:00:002007-12-03 00:00:00
 
(12 registros)

Testing this condition we have the correct answer:
bdteste=# SELECT date_trunc('month',foo) + ((CASE WHEN extract('dow' 
from date_trunc('month',foo)) > 1 THEN 8 ELSE 1 END) - extract('dow' 
from date_trunc ('month',foo)))*'1 day'::interval FROM (SELECT ('2007-' 
|| s.a || '-15')::timestamp as foo FROM generate_series(1,12) as s(a)) 
AS bar;      ?column?
--------------------- 2007-01-01 00:00:00 2007-02-05 00:00:00 2007-03-05 00:00:00 2007-04-02 00:00:00 2007-05-07
00:00:002007-06-04 00:00:00 2007-07-02 00:00:00 2007-08-06 00:00:00 2007-09-03 00:00:00 2007-10-01 00:00:00 2007-11-05
00:00:002007-12-03 00:00:00
 
(12 registros)

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