Re: string reverse fucntion?

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От Vincenzo Romano
Тема Re: string reverse fucntion?
Дата
Msg-id 3eff28921002090426v6915b3b0p4555940e0f21b406@mail.gmail.com
обсуждение исходный текст
Ответ на Re: string reverse fucntion?  (Shoaib Mir <shoaibmir@gmail.com>)
Ответы Re: string reverse fucntion?  (Pavel Stehule <pavel.stehule@gmail.com>)
Список pgsql-general
2010/2/9 Shoaib Mir <shoaibmir@gmail.com>:
> On Tue, Feb 9, 2010 at 10:31 PM, Richard Huxton <dev@archonet.com> wrote:
>>
>> On 09/02/10 09:51, AI Rumman wrote:
>>>
>>> I am using Postgresql 8.1.
>>>
>>> I have to reverse a string like 'abc' to 'cba'.
>>>
>>> Is there any function to do this?
>>
>> Nothing built-in, but you can write your own easily enough in plpgsql -
>> google a bit for examples.
>>
>
> From an old posting:
>
> CREATE FUNCTION reverse(text) RETURNS text
>     AS $_$
> DECLARE
> original alias for $1;
>       reverse_str text;
>       i int4;
> BEGIN
>     reverse_str := '';
>     FOR i IN REVERSE LENGTH(original)..1 LOOP
>       reverse_str := reverse_str || substr(original,i,1);
>     END LOOP;
> RETURN reverse_str;
> END;$_$
>     LANGUAGE plpgsql IMMUTABLE;

I think that Pavel's stuff is more interesting (and effective):

http://pgfoundry.org/projects/pstcollection/

--
Vincenzo Romano
NotOrAnd Information Technologies
NON QVIETIS MARIBVS NAVTA PERITVS

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