Decimal Separator in SELECT Clause

Question

Hi
I have the following decimal format parameters:
SQL> select value
2 from v$nls_parameters
3 where parameter = 'NLS_NUMERIC_CHARACTERS';
VALUE
If I show a number with decimal I get a comma as the decimal separator
SQL> select 10/100 from dual;
10/100
,1
But if I use a decimal separator in the SELECT clause I get:
SQL> select 100 * 1,1 from dual;
100*1 1
100 1
It doesn't work. But using a period as the decimal separator works:
SQL> select 1.1 * 100 from dual;
1.1*100
110
Maybe this is something I've never had to deal with before but I thought that the numeric format applied to the sql results and also the numbers that you used in the sql clauses.
Regards,
Néstor Boscán

Answer 1

Hi,Néstor,
user594312 wrote:
... I thought that the numeric format applied to the sql results and also the numbers that you used in the sql clauses.No; it applies to results, and it can affect implicit conversions, but it doesn't apply to SQL code.
The period (or dot, '.') is always the decimal separator in numeric literals. There is no way to change that.
Think how confusing it would be if it did apply to SQL code! For example:
WHERE   num_col  IN (1,2)Are we comparing num_col to 1 value or 2 values? Whichever it is, what if we wanted to do the opposite?
If you really wanted to use comma as the decimal separator, you could have to use strings, not numbers, and that could be a lot less efficient.
For example:
SELECT  100 * TO_NUMBER ('1,1')    -- This assumes your NLS settings are correct
FROM    dual;Of course, efficiency won't be an issue when you're selecting 1 row from dual.