Oracle 12c - SQL * Loader conditional load

Question

I'm trying to use SQL Loader and while inserting the data into the tables I need to check some conditions and insert the data.
Example:

CASE COLUMNA  
WHEN 'NULL'
   -- INSERT NULL VALUE IN IT INSTEAD OF STRING 'NULL'  
ELSE  
   -- INSERT THE DATA AS IS
END

Can we use these case statements in the SQL Loader control file? Couldn't find good examples for this any where.

Answer 1

Try adding the codition in your control file like:

load data
  APPEND INTO TABLE XXX
  fields terminated by "\t"
  TRAILING NULLCOLS
  ( --Condition which you can add.
    START_DATE "CASE WHEN length(:START_DATE ) < 10 THEN null ELSE :START_DATE END"      

  ) 

where START_DATE isthe column of the table

Answer 2

An FYI that for more complex tests or other needs that you can reuse you can also call functions or package members that return a value:

...
START_DATE "UTILITY_PKG.VALIDATE_DATE(:START_DATE)" 

Or queries (have to enclose in perentheses):

START_DATE "(select sysdate from dual)",