GROUP BY CUBE

Question

Hello,
is there any difference between those two querries ?
SELECT columnA, columnB, COUNT(*)
FROM table1
GROUP BY CUBE(columnA, columnB)
SELECT columnA, columnB, COUNT(*)
FROM table1
GROUP BY CUBE(columnB, columnA)
I know it matters when using ROLLUP, but does the order of the columns has any impact in the GROUP BY CUBE statement ?

Answer 1

Ikrischer wrote:
I never thought a query with a SET operator is sorted, I was surprised myself. First of all SET is a function, not an operator. Secondly, query with SET function is not sorted. SET function apples to nested table, not to a query. I can write something like where SET is used as select-list expression:
SQL> create or replace
  2    type SalList
  3      as table of number(7,2)
  4  /
Type created.
SQL> select  deptno,
  2          cast(collect(sal) as SalList) SalList
  3    from  emp
  4    group by deptno
  5  /
    DEPTNO SALLIST
        10 SALLIST(2450, 5000, 1300)
        20 SALLIST(800, 3000, 800, 3000, 2975)
        30 SALLIST(1500, 1500, 1250, 1500, 1250, 1250)
SQL>  select  deptno,
  2          set(cast(collect(sal) as SalList)) SalList
  3    from  emp
  4    group by deptno
  5  /
    DEPTNO SALLIST
        10 SALLIST(2450, 5000, 1300)
        20 SALLIST(800, 3000, 2975)
        30 SALLIST(1500, 1250)
SQL> SET eliminated duplicates, but do you see salary set sorted? Anyway, I think you are talking about:
SELECT  *
  FROM  TABLE(SET(nested_table))
/And this again will eliminate dups but not necessarily by sorting:
SQL> select * from table(set(NumList(3,2,1,3,3,2,1,1,2)));
COLUMN_VALUE
           3
           2
           1
SQL>  I have no idea if exam 1Z0-047 states that or not. I assume you misinterpreted what it states.
SY.