Hi @ZTC ZTC JGOTA ,

CUSTOM  = The task is executed depending on the given custom expression. The custom expression must return a date (ex: SYSDATE + 1/3600). Oracle Scheduler syntax is allowed (i.e. FREQ=WEEKLY; INTERVAL=2; BYDAY=FRI;).

For an example;

Run hourly for the first three days of every month.

FREQ=HOURLY; BYMONTHDAY=1,2,3;

More details and examples can be found in the Oracle documentation under "Using the Scheduler Calendaring Syntax". 

https://docs.oracle.com/cd/E11882_01/server.112/e25494/scheduse.htm#i1023132

@Tharindu Illangasinghe 

How could I make the task to run business day (Mon - Fri) twice a day  10 am and 5:30 pm ?

Thanks,

JL