Help needed for creating a SQLLoad control file

Question

I have 2 fields in my flat file
If field1 = field2 load only field1 into tn and aux = NULL
else if field1 != field2 load field1 into tn and field2 = aux
Here is what I have so far - I need help with the "Where"
-- ActiveNumbers.dat
-- Steve J
load data
INFILE 'active.date'
INTO TABLE tmp_ac_active
APPEND
FIELDS TERMINATED BY '|'
(tn CHAR(10), aux CHAR(10))
Thanks in advance
Steve

Answer 1

Thanks Joel
Using the document you provided here is what I came up with. I notice this is 9i documents - I'm on 8. Does the SQLLoader work the same in both versions?
This is the first time I've used this tool - No one here has even heard of it. (Well except for the DBA)
load data
INFILE 'active.date'
-- Loads tn and aux if they do not match
INTO TABLE tmp_ac_active
WHEN tn != aux
(tn CHARTERMINATED BY WHITESPACE,
aux CHAR TERMINATED BY WHITESPACE)
-- Loads only TN if both are the same
INTO TABLE tmp_ac_active
WHEN tn = aux
(tn POSITION (1:10) CHAR)