I just need to know how can I do all of this
You may have missed my prior email.
You cannot COPY directly into the target table. You must copy to a staging table. You then insert from the staging table to the target table, listing every single column, and replacing those columns you want to change with some kind of _expression_.
Basically:
INSERT INTO targettable (col1, col2, col3)
SELECT col1, col2 || '_' || nextval('sequence_name')::text, col3
FROM stagingtable;
David J.
