Re: How to find number of seconds between 2 timestamps

Woody Woodring wrote:
> I am trying to calculate a rate per second and am having trouble getting the
> number of seconds between the two timestamps to use in the formula.
>
> overview=> select extract(epoch from interval '1 day'::interval);
> date_part
> -----------
> 86400
> (1 row)
>
> overview=> select extract(epoch from interval ('2009-02-16
> 22:15:28.034567-06'::timestamp with time zone - '2009-02-15
> 22:15:28.034567-06'::timestamp with time zone));
> ERROR: syntax error at or near "'2009-02-16 22:15:28.034567-06'"

The problem is with "interval (...)" - you can say "interval 'constant'"
or "(expression)::interval".

In your case, since you are subtracting two timestamptz types you will
automatically get an interval type. So, you don't need to do anything:

select extract(epoch from ('2009-02-16 22:15:28.034567-06'::timestamp
with time zone - '2009-02-15 22:15:28.034567-06'::timestamp with time
zone));
date_part
-----------
86400
(1 row)

HTH

--
Richard Huxton
Archonet Ltd