\COPY tablename(col1,col3,col4,col2) FROM pathName WITH encoding 'UTF8' CSV HEADER NULL AS '';
                                                     ↓
\COPY tablename(col1,col3,col4,col2) FROM pathName WITH(ENCODING 'UTF8',FORMAT CSV,HEADER ON,NULL '',FORCE_NULL(col1,col3,col4,col2));