Re: BUG #3435: problem with substring function

Hello

It has little bit strange behave on 8.3. It works well, but I have to
use casting.

postgres=3D# select substring('1234' from to_number('3', '999999') for 3);
ERROR:  function pg_catalog.substring(unknown, numeric, integer) does not e=
xist
LINE 1: select substring('1234' from to_number('3', '999999') for 3)...
               ^
HINT:  No function matches the given name and argument types. You
might need to add explicit type casts.

postgres=3D# select substring('1234' from to_number('3', '999999')::int for=
 3);
 substring
-----------
 34
(1 row)

Regards
Pavel Stehule



2007/7/10, Carlos Quintero <carlos.quintero.sspa@juntadeandalucia.es>:
>
> The following bug has been logged online:
>
> Bug reference:      3435
> Logged by:          Carlos Quintero
> Email address:      carlos.quintero.sspa@juntadeandalucia.es
> PostgreSQL version: 8.2.4
> Operating system:   Linux RedHat Enterprise 3
> Description:        problem with substring function
> Details:
>
> Hi,
>
> I like to use a numerical expression as parameter for the substring
> function, but it works always as i use regular expressions. Please, try
> this:
>
> select substring('1234' from to_number('3', '999999') for 3);
>
> What returns a empty string:
>
>  substring
> -----------
>
> (1 fila)
>
> But the right result must be this:
>
> select substring('1234' from 3 for 3);
>
>  substring
> -----------
>  34
> (1 fila)
>
> If i use other numbers, i got even some errors:
>
> select substring('1234' from to_number('33', '999999') for 3);
>
> ERROR:  la expresi=F3n regular no es v=E1lida: invalid backreference numb=
er
> CONTEXTO:  funci=F3n SQL =ABsubstring=BB en la sentencia 1
>
> This is a sample, really i like to use an expression using date_part() as
> the first parameter for substring.
>
>
> Best Regards,
> Carlos
>
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