How to find the records with multiple value combinations of columns of a distinct superset combination of columns

Let's say you want to check whether the discount of online shopping cart is singular for the items of a shopping cart (Sounds strange but I am affraid this is real life in that very moment of my life. I personally feel this is a design flaw as there is a information of shopping cart level in a table of item level.)

with BASE
     as (  select distinct [DISTINCT COLUMNS]
             from [TABLE NAME]
            where [FILTER])
   , TUPS
     as (  select [SUBSET OF DISTINCT COLUMNS]
             from BASE
         group by [SUBSET OF DISTINCT COLUMNS]
           having count(*) > 1)
  select /*+ parallel(4) */
         B.*
    from BASE B
         inner join TUPS on (B.[SUBSET OF DISTINCT COLUMNS]) in ((TUPS.[SUBSET OF DISTINCT COLUMNS]))
order by B.[SUBSET OF DISTINCT COLUMNS];