oracle打印输出结果

   set serveroutput on
    declare
dbegin date;
dend date;
begin
dbegin:=to_date('2008-04-16 00:00:00','yyyy-mm-dd hh24:mi:ss');
dend:=to_date('2008-04-16 23:59:59','yyyy-mm-dd hh24:mi:ss');
dbms_output.put_line((dend-dbegin)*24*60*60);
end;