alter session set NLS_TERRITORY='FRANCE';
alter session set NLS_LENGTH_SEMANTICS='CHAR';
alter session set NLS_NUMERIC_CHARACTERS='.,';
alter session set NLS_DATE_FORMAT='DD/MM/YYYY';
alter session set NLS_TIMESTAMP_FORMAT='DD/MM/YYYY HH24:MI:SS';

set feedback off
set sqlformat insert
-- set sqlformat csv
spool /path/to/your/file.sql
select * from t;
spool off
set feedback on