Hello List,
I am writing two stored procedure which alternatively returns the dayhours and nighthours of two times. (nighthours are
consideredbetween 00:00 and 06:00).
As an example here is the getdayhours function:
------------------------------------------------------------------------------------------------
CREATE OR REPLACE FUNCTION public.getdayhours(time, time) RETURNS interval AS
'DECLARE begintime ALIAS FOR $1; endtime ALIAS FOR $2; begindate timestamp; enddate timestamp; tmpresult interval;
BEGIN IF endtime = time \'00:00\' THEN enddate := (current_date+1)+endtime; ELSE enddate :=
current_date+endtime;END IF; IF begintime < time \'06:00\' THEN begindate := current_date + time \'06:00\'; ELSE
begindate:= current_date+begintime; END IF; tmpresult := enddate-begindate; IF tmpresult<\'00:00\' THEN return
\'00:00\';ELSE return tmpresult; END IF;
END;' LANGUAGE 'plpgsql' VOLATILE;
------------------------------------------------------------------------------------------------
The working of the functions is not the problem, but the return type is. I can't seem to find a way to substract two
timevalues (or timestamp values) and get a numeric/float value. I always get the INTERVAL datatype. For example, in
steadof 4:30 i would like 4.5 as a result. I have searched the documentation but could not find any way to substract
time/timestampvalues and get a numeric/float as a result. When I try to CAST the interval to a numeric or float value I
getan error (cannot cast time without tz to ...). Same goes for trying to cast the beginvalues and then substract them.
Doesanyone have any idea how I can solve/circumvent this problem? Is there a function I can use?
I don't know if it helps but I'm going to use the functions like this:
SELECT workhour_id, employee_id, task_id, whdate, begintime, endtime, getdayhours(begintime,endtime),
getnighthours(begintime,endtime)FROM workhour
Thanks in advance.
Stijn Vanroye