will the following help to preserve the NULL.

Hi,
I have created external table script to read my pipe delimited text file.
In my data sometimes the material_group column can with empty space(not NULL).
After read the file and when selects the table it shows NULL for material_group column even it is having empty space.
Because "missing field values are null" I have mentioned.
How to keep the blanks as blank.

will the following help to preserve the NULL.

MATERIAL_GROUP CHAR(25) NULLIF (MATERIAL_GROUP=BLANKS))

Please let me know.

Thanks.

pstanand.