creating DAT file in Oracle SQL

Question

I tried to create dat file using Oracle SQL.Dat file is created but below query output is not writing in Data File.Dat file created with 0kb size.

set echo off
set feedback off
set linesize 100
set pagesize 0
set head off
set sqlprompt ''
set trimspool on
spool on
spool D:\Dat\empfeed.dat
select EMPNO||','||ENAME||','||SAL||','||NVL(COMM,0)||','||JOB||','||DEPTNO||','||HIREDATE
FROM EMP;
spool off
exit