Re: can't create index with 'dowcast' row

Louis

what if you create one "wrapper" function immutable?
some thing like this.

CREATE OR REPLACE FUNCTION myextract(timestamp )
RETURNS date AS
$BODY$
BEGIN
return extract(date from $1) ;
END;
$BODY$
LANGUAGE 'plpgsql' IMMUTABLE

best regards
mdc

--- Louis-David Mitterrand
<vindex+lists-pgsql-general(at)apartia(dot)org> escribió:

> Hi,
>
> To constraint unique'ness of my visitors to a 24h
> periode I tried
> created a index including the 'date' part of the
> created_on timestamp:
>
> CREATE UNIQUE INDEX visit_idx ON visit_buffer USING
> btree (id_session,
> id_story, created_on::date);
>
> psql:visit_pkey.sql:5: ERROR: syntax error at or
> near "::"
> LINE 1: ...buffer USING btree (id_session,
> id_story, created_on::date);
>
> and this:
>
> CREATE UNIQUE INDEX visit_idx ON visit_buffer USING
> btree (id_session, id_story, extract(date from
> created_on));
> psql:visit_pkey.sql:4: ERROR: functions in index
> expression must be marked IMMUTABLE
>
> How can I achieve what I am trying?
>
> Thanks,
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 6: explain analyze is your friend
>

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