SQL Loader: Skip column

In the control file, you can specify a filler column so that it will be skipped.

SQL> desc dept
Name
-----------------
DEPTNO
DNAME
LOC

Control File

LOAD DATA
INFILE *
INTO TABLE dept
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
(x filler integer, dname, loc)
BEGINDATA
12,RESEARCH,"SARATOGA"
10,"ACCOUNTING",CLEVELAND

It will allow you only load value for column dname and loc. The first column ID will be skipped.

One row goes to two groups

SQL> select * from tst;

C1 C2 C3
---------- ---------- ----------
1 150
1 1 80
1 2 90
1 1 130
1 3 120

Make sum on C2 based on group (c1, c2), the special requirement is
within the group of (1, null), it should include 10% of the sum of
other groups which c2 is not null. To achive this, one row will go
to 2 groups. one for itself and one maps to (c1, null).

The query will be

select
C1,
(CASE WHEN TYPE = 1 THEN C2
WHEN TYPE = 2 THEN NULL
END) C2,
SUM(CASE WHEN TYPE = 1 THEN C3
WHEN TYPE = 2 AND C2 IS NOT NULL THEN C3*0.1
ELSE NULL
END) C3_SUM
from
(
select c1, c2, sum(c3) c3
from tst
group by c1, c2
), (select 1 type from dual union all select 2 type from dual
)
group by
C1,
(CASE WHEN TYPE = 1 THEN C2
WHEN TYPE = 2 THEN NULL
END)

and result is

C1 C2 C3_SUM
---------- ---------- ----------
1 192
1 1 210
1 2 90
1 3 120