Re: [SQL] index on aggregate function

Remigiusz Sokolowski ha scritto:

> > > > I somewhere read that it is possible to create an index on aggregate functions
> > > > in PostgreSQL. Which syntax do I have to use for it?
> > > >
> > > > test=> CREATE TABLE test ( name VARCHAR(32) );
> > > > CREATE
> > > > test=> CREATE INDEX test_idx ON test lower(name);
> > > > ERROR:  parser: parse error at or near "lower"
> > > >
> > > > gives me a parser error.
> > >
> > > Right syntax is
> > > CREATE INDEX test_idx ON test (lower(name) text_ops);
> > > I try it and index was generated without error
> > >     Rem
> >
> > Well, that exact statement gives me:
> >
> > ERROR: BuildFuncTupleDesc: function 'lower(varchar)' does not exist
> >
> > I also tried varchar_ops and char_ops instead of text_ops, but that does not
> > resolve the problem. I'm using PostgreSQL 6.4.2 on Linux without problems so
> > far.
>
> I have holidays and now have to read so much mails, that I can't find if
> there were any other suggestions about that. AFAIK there is no lower()
> function for varchar type and this is a problem - solution is to use text
> type or create function lower() for varchar type.
>         Rem
>
> -------------------------------------------------------------------*------------
> Remigiusz Sokolowski      e-mail: rems@gdansk.sprint.pl           * *
> -----------------------------------------------------------------*****----------

--lower() works with varchar...

prova=> CREATE TABLE test ( name VARCHAR(32) );
CREATE
prova=> insert into test values ('AAAA');
INSERT 188475 1
prova=> select lower(name) from test;
lower
-----
aaaa
(1 row)

but it doesn't work on create index...

prova=> drop table test;
DROP
prova=> CREATE TABLE test ( name VARCHAR(32) );
CREATE
prova=> CREATE INDEX test_idx ON test lower(nome);
ERROR:  parser: parse error at or near "lower"

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                               - Jose' -

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