> I, as a user would be happier if we also have to_regprocedure() and
> to_regoperator(). The following query looks a valid use-case where one
> needs to find if a particular function exists. Using to_regproc('sum') does
> not make sense here because it will return InvalidOid, which will not tell
> us whether that is because there is no such function or whether there are
> duplicate function names.
> select * from pg_proc where oid = to_regprocedure('sum(int)');
I doubt the value of the use case above. Hasn't psql already done an
excellent job?
test=# \df sum
List of functions
Schema | Name | Result data type | Argument data types | Type
------------+------+------------------+---------------------+------
pg_catalog | sum | numeric | bigint | agg
pg_catalog | sum | double precision | double precision | agg
pg_catalog | sum | bigint | integer | agg
pg_catalog | sum | interval | interval | agg
pg_catalog | sum | money | money | agg
pg_catalog | sum | numeric | numeric | agg
pg_catalog | sum | real | real | agg
pg_catalog | sum | bigint | smallint | agg
(8 rows)
If you need simliar functionality in the backend, you could always
define a view using the query generated by psql.
********* QUERY **********
SELECT n.nspname as "Schema",
p.proname as "Name",
pg_catalog.pg_get_function_result(p.oid) as "Result data type",
pg_catalog.pg_get_function_arguments(p.oid) as "Argument data types",
CASE
WHEN p.proisagg THEN 'agg'
WHEN p.proiswindow THEN 'window'
WHEN p.prorettype = 'pg_catalog.trigger'::pg_catalog.regtype THEN 'trigger'
ELSE 'normal'
END as "Type"
FROM pg_catalog.pg_proc p
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace
WHERE p.proname ~ '^(sum)$'
AND pg_catalog.pg_function_is_visible(p.oid)
ORDER BY 1, 2, 4;
**************************
Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp
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