How to sum amount with columns that have complicated structures, such as decode?

Hi everyone,

This could be an easy question for many of you.  I need to sum up some amount columns in my SQL statement.  However, I also have some columns with complicated structures which caused problem when I put them in grouping section.  Here are two types of examples:

1.  DECODE(PLL.PO_RELEASE_ID, NULL, NVL(POH.AUTHORIZATION_STATUS, 'INCOMPLETE'), NVL (POR.AUTHORIZATION_STATUS,'INCOMPLETE')) STATUS

2.  CC.SEGMENT1||'-'||CC.SEGMENT2||'-'||CC.SEGMENT3||'-'||CC.SEGMENT4||'-'||CC.SEGMENT5||'-'||CC.SEGMENT6 ACCOUNTING

When I put them in grouping section without name part, SQL finish normal but there is no row returned.  I supposed to have thousands and thousands rows back.  Not sure how to get around of this.