Date comparison question.

I have a function workday.getday(nn) that returns a date.

For instance: select workday.getday(5) from dual returns 07-MAY-98

Today 5/20/98 if I: select sysdate - 13 from dual it also returns 07-MAY-98

if I use DECODE to test the equivalence of these two dates it returns a false code.

select decode( sysdate-13, workday.getday( 5 ), 1, 0 ) from dual
returns 0

but if I convert from date to CHAR it works returns a true code.

select decode( to_char( sysdate-13, 'YYMMDD' ),

               to_char( workday.getday( 5 ), 'YYMMDD' ), 1, 0 )
  from dual
returns 1

Why does the comparison not work when both are left in date format?

Michael. Received on Wed May 20 1998 - 17:40:24 CDT