CREATE FUNCTION
CREATE [OR REPLACE] FUNCTION [schema.
]function_name
[(argument
[IN]datatype
[,argument [IN]datatype
.)] RETURNdatatype
{IS | AS}pl/sql_function_code
Creates a standalone function ( function_name).
Specifies that if the function exists, it is to be replaced.
Specifies the name of an argument to the function.
Specifies that a value must be supplied for the argument when calling the function.
Specifies the datatype of the argument; this can be any PL/SQL datatype.
Specifies the datatype (any PL/SQL datatype) of the function code ( pl/sql_function_code). You must specify either the IS or AS keyword.
Specifies the function code, written in PL/SQL.