is it possible to use the DECODE function (or any other user function) in EXTERNAL TABLE ACCESS PARAMETER syntax?
it is in SQL LOADER isn't it?

in the example below i want to put a default date in case the birthdate is null, and put the city in the address field by using a function i wrote.
ther's a problem with the "double-quoted-string" (KUP-01005)
what is wrong in the syntax? and how can i do it otherwise?

create table ext_tab
(ID number(10),
NAME varchar2(60),
ADDRESS varchar2(100))
organization external
(type oracle_loader
default directory my_dir
access parameters
(fields terminated by ','
missing field values are null
(id position(1:9) integer external(10),
name position(10:59) char nullif name=BLANK,
birthdate position(60:69) date "DD/MM/YYYY" "DECODE(:birthdate,'00/00/0000', '01/01/1900',:birthdate)",
address position(70:169) char nullif address=BLANK "get_city(:address)"
location ('source.scv'')