SQL> select * from p1;

        ID A          B          C                   I
---------- ---------- ---------- ---------- ----------
         1 one        test1      test2               5
         2 two        test1      test3               3
         3 three      test1      test4               8
         4 three      test1      test4              10

SQL> select a,b,sum(i) over (partition by a) from p1 ;

A          B          SUM(I)OVER(PARTITIONBYA)
---------- ---------- ------------------------
one        test1                             5
three      test1                            18
three      test1                            18
two        test1                             3

SQL> select a,b,sum(i) over (partition by b) from p1 ;

A          B          SUM(I)OVER(PARTITIONBYB)
---------- ---------- ------------------------
one        test1                            26
three      test1                            26
three      test1                            26
two        test1                            26

SQL>