Answers for "Oracle fuctions syntax"

oracle function

CREATE OR REPLACE FUNCTION to_date_check_null(dateString IN VARCHAR2, 
	dateFormat IN VARCHAR2) RETURN DATE IS
BEGIN 
    IF dateString IS NULL THEN
        return NULL;
    ELSE
        return to_date(dateString, dateFormat);
    END IF;
END;

syntax of function in oracle

CREATE [OR REPLACE] FUNCTION function_name
   [ (parameter [,parameter]) ]

   RETURN return_datatype

IS | AS

   [declaration_section]

BEGIN
   executable_section

[EXCEPTION
   exception_section]

END [function_name];