Re: Why length(to_char(1::integer, '9')) = 2 ?

On 03/09/2011 09:59 AM, Dmitriy Igrishin wrote:
>
>
> 2011/3/9 Adrian Klaver <adrian.klaver@gmail.com
> <mailto:adrian.klaver@gmail.com>>
>
>     On Wednesday, March 09, 2011 5:34:41 am Dmitriy Igrishin wrote:
>
>      >
>      > But I am missing something or there is a documentation inaccuracy:
>      >
>     http://www.postgresql.org/docs/9.0/static/functions-formatting.html#FUNCTIO
>      > NS-FORMATTING-NUMERICMOD-TABLEsays: fill mode (suppress padding
>     blanks and
>      > zeroes)
>      >
>      > Test:
>      > dmitigr=> select to_char(12,'FM0009');
>      >  to_char
>      > ---------
>      >  0012
>      >
>      > dmitigr=> select length(to_char(12,'FM0009'));
>      >  length
>      > --------
>      >       4
>      >
>      > So, FM suppresses only padding blanks not zeroes...
>      >
>      > Any comments?
>      >
>
>     test(5432)aklaver=>select to_char(12,'9999');
>       to_char
>     ---------
>         12
>
>     test(5432)aklaver=>select to_char(12,'FM9999');
>       to_char
>     ---------
>       12
>
>     It is a little confusing, but you asked for the 0 in your
>     specification so they
>     are not considered padding.
>
>     Look at the examples in the table listed below to get an idea of
>     what I am
>     talking about.
>     http://www.postgresql.org/docs/9.0/static/functions-formatting.html
>     Table 9-25
>
> Yes, I see, thanks!
>
> I just talking about phrase "fill mode (suppress padding blanks and zeroes)"
> in the documentation should be rephrased to "fill mode (suppress padding
> blanks)".

To get technical it means suppress unspecified padding O's. See below
for example.

>
> Or I misunderstood what is "padding zeroes" without explicitly
> specification "0" pattern in the format format template...

This combination from the example table shows that:

to_char(-0.1, 'FM9.99')    '-.1'
to_char(0.1, '0.9')    ' 0.1'

The 0 in 0.1 is not strictly needed, so if you use FM it will be suppressed.


>
>
>
>     --
>     Adrian Klaver
>     adrian.klaver@gmail.com <mailto:adrian.klaver@gmail.com>
>
>
>
>
> --
> // Dmitriy.
>
>


--
Adrian Klaver
adrian.klaver@gmail.com