Re: || operator

On 3 September 2014 15:20, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:

> Hi
>
> you can define || operator for char(N) type
>
> postgres=# select oprname, oprleft::regtype, oprright::regtype from
> pg_operator where oprname = '||'
> ;
> oprname | oprleft | oprright
> ---------+-------------+-------------
> || | bytea | bytea
> || | text | text
> || | text | anynonarray
> || | bit varying | bit varying
> || | anyarray | anyarray
> || | anyarray | anyelement
> || | anyelement | anyarray
> || | anynonarray | text
> || | tsvector | tsvector
> || | tsquery | tsquery
> (10 rows)
>
>
> it is defined only for text, and value char(n) is reduced when it is
> converted probably
>
> postgres=# create or replace function concat_character(character,
> character) returns text as $$ select concat($1,$1)$$ language sql;
> CREATE FUNCTION
>
> postgres=# create operator || (procedure = concat_character, leftarg =
> character, rightarg = character);
> CREATE OPERATOR
> postgres=# select 'abc '::char(7) || 'dbe '::char(6);
> ?column?
> ----------------
> abc abc
> (1 row)
>
> concat is variadic "any" function, so implicit casting character(n) ->
> text is not used there
>
>
> Pavel
>
>

Hi Pavel,
I think we should have this in core, as this definitely is a bug.

Szymon