Re: How can I list the function.

That actually depends on the nature of function as well. According to the
PostgreSQL manual:
\df [ pattern ]
\df+ [ pattern ]

Lists available functions, together with their argument and return types. If
pattern is specified, only functions whose names match the pattern are
shown. If the form \df+ is used, additional information about each function,
including language and description, is shown.

Note: To look up functions taking argument or returning values of a specific
type, use your pager's search capability to scroll through the \df output.

To reduce clutter, \df does not show data type I/O functions. This is
implemented by ignoring functions that accept or return type cstring.

I just tried the following at my end with 8.2:

CREATE FUNCTION add(integer, integer) RETURNS integer
AS 'select $1 + $2;'
LANGUAGE SQL
IMMUTABLE
RETURNS NULL ON NULL INPUT;

and then doing a

\df+ add

did show me the correct output...

You can also try the following to get the same type of results:

select proargtypes, prorettype, prosrc from pg_proc where proname =
'delete_old';

---
Shoaib Mir
EnterpriseDB (www.enterprisedb.com)

On 2/1/07, Harvey, Allan AC <HarveyA(at)onesteel(dot)com> wrote:
>
> I know the function is there.
> What am I doing wrong?
>
> galvdb=#
> galvdb=# \df+ delete_old
> List of functions
> Result data type | Schema | Name | Argument data types | Owner | Language
> | Source code | Description
>
> ------------------+--------+------+---------------------+-------+----------+-------------+-------------
> (0 rows)
>
> galvdb=# select delete_old();
> delete_old
> ------------
> 482
> (1 row)
>
> galvdb=# select version();
> version
>
> -------------------------------------------------------------------------------------
> PostgreSQL 8.2.0 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.3.3(SuSE Linux)
> (1 row)
>
> galvdb=#
>
>
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