ГРЕШКА на Oracle:ORA-00900:невалиден SQL оператор

Заменете FLOAT(2) само с FLOAT :

CREATE OR REPLACE TYPE EmployeeType AS OBJECT (
    EmployeeNumber NUMBER,
    EmployeeName VARCHAR2(150),
    EmployeeAddress VARCHAR2(255),
    MAP MEMBER FUNCTION getEmployeeNumber RETURN NUMBER,
    MEMBER FUNCTION CalculateSalary RETURN FLOAT
)
NOT FINAL;
/
CREATE OR REPLACE TYPE BODY EmployeeType AS

    MAP MEMBER FUNCTION getEmployeeNumber RETURN NUMBER IS
    BEGIN
        RETURN EmployeeNumber;
    END;
     -- function that can be overriden by subtypes, make abstract
    MEMBER FUNCTION CalculateSalary RETURN FLOAT IS
    BEGIN
         -- function returns empty, has to be overwritten by fulltimeemployee
        RETURN 0.00;
    END;
END; 
/

Документацията за CREATE TYPE не споменава това, но можете да намерите обяснението в темата, свързана с CREATE FUNCTION :http://docs.oracle.com/cd/ B28359_01/appdev.111/b28370/create_function.htm RETURN тип данни