TO_NUMBER getting invalid number error

Question

I want to use TO_NUMBER function to converse some float number,
but the following query always gets invalid number error:
select to_number('12.1073') from dual;
but if I add the format in, it runs as expected:
select to_number('12.1073', '99.9999') from dual;
From the syntax, the format parameter is optional, is it only optional for integers?
Thanks!

Answer 1

Same here.
So, or you replace dot by comma, or you change the territory (or nls_numeric_characters) defined for your session :
SQL> select to_number('12.1073') from dual;
select to_number('12.1073') from dual
ERROR at line 1:
ORA-01722: invalid number
Elapsed: 00:00:00.00
SQL> alter session set nls_territory='america';
Session altered.
Elapsed: 00:00:00.00
SQL> select to_number('12.1073') from dual;
TO_NUMBER('12.1073')
             12.1073
Elapsed: 00:00:00.00
SQL> alter session set nls_territory='france';
Session altered.
Elapsed: 00:00:00.00
SQL> select to_number('12.1073') from dual;
select to_number('12.1073') from dual
ERROR at line 1:
ORA-01722: invalid number
Elapsed: 00:00:00.00
SQL> alter session set nls_numeric_characters='.,';
Session altered.
Elapsed: 00:00:00.00
SQL> select to_number('12.1073') from dual;
TO_NUMBER('12.1073')
             12.1073
Elapsed: 00:00:00.00
SQL> Nicolas.