CREATE [ OR REPLACE ] FUNCTION [ schema. ] function_name [ ( parameter_declaration [, parameter_declaration] ) ] RETURN datatype [ { invoker_rights_clause | DETERMINISTIC | parallel_enable_clause | RESULT_CACHE [ relies_on_clause ] }... ] { { AGGREGATE | PIPELINED } USING [ schema. ] implementation_type | [ PIPELINED ] { IS | AS } { [ declare_section ] body | call_spec | EXTERNAL } } ;