Обсуждение: EPCOH: extract returns millisecs too?

 From the iDocs:

epoch

     For date and timestamp values, the number of seconds since
1970-01-01 00:00:00-00 (Result may be negative.); for interval values,
the total number of seconds in the interval

SELECT EXTRACT(EPOCH FROM TIMESTAMP '2001-02-16 20:38:40');
Result: 982352320

But if I seem to get milliseconds too in my queries:

$ psql sessions -c "SELECT EXTRACT(EPOCH FROM current_timestamp) as now"
        now
------------------
  1029298563.74248
(1 row)

Are the Docs out of date? How can I get EXTRACT to only return seconds?

Jc

Jean-Christian Imbeault <jc@mega-bucks.co.jp> writes:
> [ the docs state ]

> SELECT EXTRACT(EPOCH FROM TIMESTAMP '2001-02-16 20:38:40');
> Result: 982352320

Sure, that is an exact-second timestamp; it's not going to have any
fractional-second component.

> But if I seem to get milliseconds too in my queries:

> $ psql sessions -c "SELECT EXTRACT(EPOCH FROM current_timestamp) as now"
>         now
> ------------------
>   1029298563.74248
> (1 row)

> Are the Docs out of date? How can I get EXTRACT to only return seconds?

We return fractional seconds in current_timestamp since 7.2.  You can
use current_timestamp(0) to round the result to seconds, or just apply
round() to EXTRACT's result.

            regards, tom lane