Trouble with dates

Question

Hello. I'm trying to do some operation with a date field. This date field normally has the actual date.
I need to do select (sysdate-myDate)*24*60*60 from myTable where id=xxx
The problem is that sysdate-myDate returns void instead of 0. I don't understand that. sysdate-sysdate or myDate-myDate returns 0
I'm I missing something?

Answer 1

Maybe SQL Developer is doing something funny based on a setting or something.
This works in SQL Plus:
SQL> select * from myTable;
ID    MYDATE
xxx   31-JAN-2007
xxx   28-FEB-2007
xxx
xxx   31-MAR-2007
xxx
SQL> select id, myDate, (sysdate-myDate)*24*60*60 no_seconds
  2  from   myTable
  3  where  id = 'xxx';
ID    MYDATE                NO_SECONDS
xxx   31-JAN-2007              9715534
xxx   28-FEB-2007              7296334
xxx
xxx   31-MAR-2007              4617934
xxxThe calculated column is null if the mydate column is null.