How do I convert an interval into a number of hours with postgres?

问题

Say I have an interval like

4 days 10:00:00

in postgres. How do I convert that to a number of hours (106 in this case?) Is there a function or should I bite the bullet and do something like

extract(days, my_interval) * 24 + extract(hours, my_interval)

回答1:

Probably the easiest way is:

SELECT EXTRACT(epoch FROM my_interval)/3600

回答2:

If you want integer i.e. number of days:

SELECT (EXTRACT(epoch FROM (SELECT (NOW() - '2014-08-02 08:10:56')))/86400)::int

回答3:

To get the number of days the easiest way would be:

SELECT EXTRACT(DAY FROM NOW() - '2014-08-02 08:10:56');

As far as I know it would return the same as:

SELECT (EXTRACT(epoch FROM (SELECT (NOW() - '2014-08-02 08:10:56')))/86400)::int;

回答4:

select floor((date_part('epoch', order_time - '2016-09-05 00:00:00') / 3600)), count(*)
from od_a_week
group by floor((date_part('epoch', order_time - '2016-09-05 00:00:00') / 3600));

The ::int conversion follows the principle of rounding. If you want a different result such as rounding down, you can use the corresponding math function such as floor.

回答5:

If you convert table field:

Define the field so it contains seconds:

 CREATE TABLE IF NOT EXISTS test (
     ...
     field        INTERVAL SECOND(0)
 );

Extract the value. Remember to cast to int other wise you can get an unpleasant surprise once the intervals are big:

EXTRACT(EPOCH FROM field)::int

回答6:

         select date 'now()' - date '1955-12-15';

Here is the simple query which calculates total no of days.

来源：https://stackoverflow.com/questions/952493/how-do-i-convert-an-interval-into-a-number-of-hours-with-postgres

标签

datetime

postgresql

intervals