Re: how to convert a time interval to seconds?

On Tue, Sep 12, 2006 at 10:39:25AM -0400, Chansup Byun wrote:
> I searched how to convert a time interval to seconds but failed to find
> an example.

Searching the list archives for "interval to seconds" returns many
examples.  See also "Date/Time Functions and Operators" in the
documentation.

http://archives.postgresql.org/
http://www.postgresql.org/docs/8.1/interactive/functions-datetime.html

EXTRACT(EPOCH FROM interval_value)

> I want to convert the following wait_time column into seconds. How can I
> do that? The datatype for the wait_time is time without timezone.
>
>  job_number | task_number |   submission_time   | wait_time
> ------------+-------------+---------------------+-----------
>          56 |           0 | 2006-04-13 08:47:53 | 00:01:28

Does wait_time represent a duration?  If so then why is it a time
without timezone instead of an interval?

--
Michael Fuhr