Time in Postgres

gistfile1.sh

lxneng=# SELECT 'YESTERDAY'::date, 'TODAY'::date, 'TOMORROW'::date;
    date    |    date    |    date
------------+------------+------------
 2013-08-07 | 2013-08-08 | 2013-08-09
(1 row)

lxneng=# select now();
              now
-------------------------------
 2013-08-08 09:09:32.687512+08
(1 row)

lxneng=# select now() + '1 days'::interval;
           ?column?
-------------------------------
 2013-08-09 09:09:38.610495+08
(1 row)

lxneng=# SELECT * FROM generate_series('2012-02-26'::date, '2012-03-02'::date, '1 day'::interval);
    generate_series
------------------------
 2012-02-26 00:00:00+08
 2012-02-27 00:00:00+08
 2012-02-28 00:00:00+08
 2012-02-29 00:00:00+08
 2012-03-01 00:00:00+08
 2012-03-02 00:00:00+08
(6 rows)