> -----Mensagem original----- > De: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general- > owner@xxxxxxxxxxxxxx] Em nome de Harald Fuchs > Enviada em: terça-feira, 27 de setembro de 2011 07:01 > Para: pgsql-general@xxxxxxxxxxxxxx > Assunto: Re: Does postgresql 9.0.4 use index on PREFIX%SUFFIX > queries? > > In article <CABRT9RDxHKCxrq8wboHnikpF- > CGgkteJWdw3Q2_kXFEdP4prTw@xxxxxxxxxxxxxx>, > Marti Raudsepp <marti@xxxxxxxxx> writes: > > > Ah, the reverse() function is not included with PostgreSQL 9.0 yet. > > This is what I use: > > > CREATE FUNCTION reverse(input text) RETURNS text LANGUAGE plpgsql > > IMMUTABLE STRICT AS $$ DECLARE > > result text = ''; > > i int; > > BEGIN > > FOR i IN 1..length(input) BY 2 LOOP > > result = substr(input,i+1,1) || substr(input,i,1) || result; > > END LOOP; > > RETURN result; > > END$$; > > Pavel Stehule has found a better solution for that: > > CREATE OR REPLACE FUNCTION reverse(text) RETURNS text AS $$ > SELECT string_agg(substring($1 FROM i FOR 1), '') > FROM generate_series(length($1), 1, -1) g(i) $$ language sql; > > But the best, of course, is upgrading to 9.1. Upgrade to 9.1 into production servers is not na option. It will take about a year before I can migrate all databases and establish replication and everything else (probably, Christams Holidays in December or Carnival in February next). Some users demand 24x7 from this databases, I can't just say "stop for one-two hour". Thanks for the tip, I'll give a try for both funtions and let you know the results. Would save time for future... Regards, Edson. > > > -- > Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make > changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general
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