When subtracting timestamps
the return value is an interval
data-type. Is there an elegant way to convert this value into the total number of (milli/micro) seconds in the interval, i.e. an integer.
The following would work, but it's not very pretty:
select abs( extract( second from interval_difference )
+ extract( minute from interval_difference ) * 60
+ extract( hour from interval_difference ) * 60 * 60
+ extract( day from interval_difference ) * 60 * 60 * 24
)
from ( select systimestamp - (systimestamp - 1) as interval_difference
from dual )
Is there a more elegant method in SQL or PL/SQL?
An easy way:
select extract(day from (ts1-ts2)*86400) from dual;
The idea is to convert the interval value into days by times 86400 (= 24*60*60). Then extract the 'day' value which is actually second value we wanted.