Hi,

I am Learning Data Loading With Sql Loader.i written some basic control files(with out using Clauses) then data loaded well. but i did not understand the clauses like NULLIF, CHAR, DEFAULTIF etc. So please tell me why we use this Clauses in Control File. For Example below is the control file for reference.

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OPTIONS (SKIP = 1)
LOAD DATA CHARACTERSET WE8MSWIN1252
INFILE '$FILE'
APPEND
INTO TABLE Customer_table
FIELDS TERMINATED BY '|'
TRAILING NULLCOLS
(
"SOURCE_SYSTEM_NAME" CHAR NULLIF "SOURCE_SYSTEM_NAME"=BLANKS,
"OPERATING_UNIT" CHAR NULLIF "OPERATING_UNIT"=BLANKS,
"CUSTOMER_NAME" CHAR NULLIF "CUSTOMER_NAME"=BLANKS,
"LEGACY_CUSTOMER_NUMBER" CHAR NULLIF "LEGACY_CUSTOMER_NUMBER"=BLANKS,
"CUST_ACCT_NAME" CHAR NULLIF "CUST_ACCT_NAME"=BLANKS,
"SITE_NAME" CHAR NULLIF "SITE_NAME"=BLANKS,
"SITE_USAGE" CHAR NULLIF "SITE_USAGE"=BLANKS,
"CONTACT_FIRST_NAME" CHAR NULLIF "CONTACT_FIRST_NAME"=BLANKS,
"CONTACT_LAST_NAME" CHAR NULLIF "CONTACT_LAST_NAME"=BLANKS,
"CONTACT_EMAIL" CHAR NULLIF "CONTACT_EMAIL"=BLANKS,
"CONTACT_ROLE" CHAR NULLIF "CONTACT_ROLE"=BLANKS,
"CONTACT_PHONE" CHAR NULLIF "CONTACT_PHONE"=BLANKS,
"MOBILE_NUMBER" CHAR NULLIF "MOBILE_NUMBER"=BLANKS,
"FAX_NUMBER" CHAR NULLIF "FAX_NUMBER"=BLANKS,
"PHONE_COUNTRY_CODE" CHAR NULLIF "PHONE_COUNTRY_CODE"=BLANKS,
"PHONE_AREA_CODE" CHAR NULLIF "PHONE_AREA_CODE"=BLANKS,
CONTACT_STATUS "Trim(Replace(:CONTACT_STATUS, chr(13), ''))",
CREATED_BY "FND_GLOBAL.LOGIN_ID",
CREATION_DATE sysdate,
LAST_UPDATED_BY "FND_GLOBAL.LOGIN_ID",
LAST_UPDATE_DATE sysdate,
Last_Update_Login "FND_GLOBAL.LOGIN_ID"
)

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I loaded data by removing null if and char second time keeping them but i did not notice any difference between them.

NULLIF "FIELD"=BLANKS