Re: BUG #6217: to_char() gives incorrect output for very small float values

On Tue, Sep 20, 2011 at 8:52 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> However, it would
> be interesting to know what Oracle etc do with NaN and Infinity,
> assuming they even support such numbers.

Note that it looks like NUMBER cannot store either Infinity or NaN.
They can only occur in BINARY_FLOAT and BINARY_DOUBLE. From the docs:

> If a BINARY_FLOAT or BINARY_DOUBLE value is converted to CHAR or NCHAR, and the input is either infinity or NaN (not a number), then Oracle always returns the pound signs to replace the value.

And testing shows:

SQL> select to_char(cast('NAN' as binary_float), 'FM9999.9999') from dual;

TO_CHAR(CA
----------
##########

SQL> select to_char(cast('-Inf' as binary_float), 'FM9999.9999') from dual;

TO_CHAR(CA
----------
##########

SQL> select to_char(cast('+Inf' as binary_float), 'FM9999.9999') from dual;

TO_CHAR(CA
----------
##########

--
greg