Re: reverse strpos? - Mailing list pgsql-general

From A. Kretschmer
Subject Re: reverse strpos?
Date
Msg-id 20071112170109.GA18644@a-kretschmer.de
Whole thread Raw
In response to Re: reverse strpos?  (David Fetter <david@fetter.org>)
List pgsql-general
am  Mon, dem 12.11.2007, um  8:48:29 -0800 mailte David Fetter folgendes:
> > > Is there a function that?ll return the position of the last
> > > occurance of a char in a string?
> > >
> >
> > write a function to revert the string and use strpos().
> >
> > create or replace function rev(varchar) returns varchar as $$
> > declare
> > ...
> > $$ language plpgsql immutable;
> >
> >
> > Andreas
>
> PL/Perl might be easier:
>
> CREATE OR REPLACE FUNCTION rev(TEXT)
> RETURNS TEXT
> IMMUTABLE
> LANGUAGE plperl
> AS $$
> return reverse($_[0]);
> $$;

heh, the PERL-Guru ;-)


>
> CREATE OR REPLACE FUNCTION rev(TEXT)
> RETURNS TEXT
> IMMUTABLE
> LANGUAGE SQL
> AS $$
> SELECT array_to_string(
>     ARRAY(
>         SELECT substr($1,i,1)
>         FROM generate_series(length($1),1,-1) AS i
>     ),
>     ''
> );
> $$;

Nice.

The generate_series()-function are really great.


Andreas
--
Andreas Kretschmer
Kontakt:  Heynitz: 035242/47150,   D1: 0160/7141639 (mehr: -> Header)
GnuPG-ID:   0x3FFF606C, privat 0x7F4584DA   http://wwwkeys.de.pgp.net

pgsql-general by date:

Previous
From: "Scott Marlowe"
Date:
Subject: Re: update record with two-column primary key
Next
From: Greg Smith
Date:
Subject: Re: Linux v.s. Mac OS-X Performance