| specific_catalog | sql_identifier | Name of the database containing the function (always the current database) | 
| specific_schema | sql_identifier | Name of the schema containing the function | 
| specific_name | sql_identifier | The "specific name" of the function.  This is a
       name that uniquely identifies the function in the schema, even
       if the real name of the function is overloaded.  The format of
       the specific name is not defined, it should only be used to
       compare it to other instances of specific routine names. | 
| routine_catalog | sql_identifier | Name of the database containing the function (always the current database) | 
| routine_schema | sql_identifier | Name of the schema containing the function | 
| routine_name | sql_identifier | Name of the function (may be duplicated in case of overloading) | 
| routine_type | character_data | Always FUNCTION (In the future there might
       be other types of routines.) | 
| module_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| module_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| module_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| udt_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| udt_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| udt_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| data_type | character_data | Return data type of the function, if it is a built-in type, or
       ARRAY if it is some array (in that case, see
       the view element_types), else
       USER-DEFINED (in that case, the type is
       identified in type_udt_name and associated
       columns). | 
| character_maximum_length | cardinal_number | Always null, since this information is not applied to return data types in PostgreSQL | 
| character_octet_length | cardinal_number | Always null, since this information is not applied to return data types in PostgreSQL | 
| character_set_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| character_set_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| character_set_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| collation_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| collation_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| collation_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| numeric_precision | cardinal_number | Always null, since this information is not applied to return data types in PostgreSQL | 
| numeric_precision_radix | cardinal_number | Always null, since this information is not applied to return data types in PostgreSQL | 
| numeric_scale | cardinal_number | Always null, since this information is not applied to return data types in PostgreSQL | 
| datetime_precision | cardinal_number | Always null, since this information is not applied to return data types in PostgreSQL | 
| interval_type | character_data | Always null, since this information is not applied to return data types in PostgreSQL | 
| interval_precision | character_data | Always null, since this information is not applied to return data types in PostgreSQL | 
| type_udt_catalog | sql_identifier | Name of the database that the return data type of the function
       is defined in (always the current database) | 
| type_udt_schema | sql_identifier | Name of the schema that the return data type of the function is
       defined in | 
| type_udt_name | sql_identifier | Name of the return data type of the function | 
| scope_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| scope_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| scope_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| maximum_cardinality | cardinal_number | Always null, because arrays always have unlimited maximum cardinality in PostgreSQL | 
| dtd_identifier | sql_identifier | An identifier of the data type descriptor of the return data
       type of this function, unique among the data type descriptors
       pertaining to the function.  This is mainly useful for joining
       with other instances of such identifiers.  (The specific format
       of the identifier is not defined and not guaranteed to remain
       the same in future versions.) | 
| routine_body | character_data | If the function is an SQL function, then
       SQL, else EXTERNAL. | 
| routine_definition | character_data | The source text of the function (null if the function is not
       owned by a currently enabled role).  (According to the SQL
       standard, this column is only applicable if
       routine_body is SQL, but
       in PostgreSQL it will contain
       whatever source text was specified when the function was
       created.) | 
| external_name | character_data | If this function is a C function, then the external name (link
       symbol) of the function; else null.  (This works out to be the
       same value that is shown in
       routine_definition.) | 
| external_language | character_data | The language the function is written in | 
| parameter_style | character_data | Always GENERAL (The SQL standard defines
       other parameter styles, which are not available in PostgreSQL.) | 
| is_deterministic | character_data | If the function is declared immutable (called deterministic in
       the SQL standard), then YES, else
       NO.  (You cannot query the other volatility
       levels available in PostgreSQL through the information schema.) | 
| sql_data_access | character_data | Always MODIFIES, meaning that the function
       possibly modifies SQL data.  This information is not useful for
       PostgreSQL. | 
| is_null_call | character_data | If the function automatically returns null if any of its
       arguments are null, then YES, else
       NO. | 
| sql_path | character_data | Applies to a feature not available in PostgreSQL | 
| schema_level_routine | character_data | Always YES (The opposite would be a method
       of a user-defined type, which is a feature not available in
       PostgreSQL.) | 
| max_dynamic_result_sets | cardinal_number | Applies to a feature not available in PostgreSQL | 
| is_user_defined_cast | character_data | Applies to a feature not available in PostgreSQL | 
| is_implicitly_invocable | character_data | Applies to a feature not available in PostgreSQL | 
| security_type | character_data | If the function runs with the privileges of the current user,
       then INVOKER, if the function runs with the
       privileges of the user who defined it, then
       DEFINER. | 
| to_sql_specific_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| to_sql_specific_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| to_sql_specific_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| as_locator | character_data | Applies to a feature not available in PostgreSQL | 
| created | time_stamp | Applies to a feature not available in PostgreSQL | 
| last_altered | time_stamp | Applies to a feature not available in PostgreSQL | 
| new_savepoint_level | character_data | Applies to a feature not available in PostgreSQL | 
| is_udt_dependent | character_data | Applies to a feature not available in PostgreSQL | 
| result_cast_from_data_type | character_data | Applies to a feature not available in PostgreSQL | 
| result_cast_as_locator | character_data | Applies to a feature not available in PostgreSQL | 
| result_cast_char_max_length | cardinal_number | Applies to a feature not available in PostgreSQL | 
| result_cast_char_octet_length | character_data | Applies to a feature not available in PostgreSQL | 
| result_cast_char_set_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_char_set_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_char_set_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_collation_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_collation_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_collation_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_numeric_precision | cardinal_number | Applies to a feature not available in PostgreSQL | 
| result_cast_numeric_precision_radix | cardinal_number | Applies to a feature not available in PostgreSQL | 
| result_cast_numeric_scale | cardinal_number | Applies to a feature not available in PostgreSQL | 
| result_cast_datetime_precision | character_data | Applies to a feature not available in PostgreSQL | 
| result_cast_interval_type | character_data | Applies to a feature not available in PostgreSQL | 
| result_cast_interval_precision | character_data | Applies to a feature not available in PostgreSQL | 
| result_cast_type_udt_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_type_udt_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_type_udt_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_scope_catalog | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_scope_schema | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_scope_name | sql_identifier | Applies to a feature not available in PostgreSQL | 
| result_cast_maximum_cardinality | cardinal_number | Applies to a feature not available in PostgreSQL | 
| result_cast_dtd_identifier | sql_identifier | Applies to a feature not available in PostgreSQL |