-- create
CREATE TABLE EMPLOYEE (
  empId int,
  from_datetime DATETIME default null,
  to_datetime DATETIME default null
);

-- insert
INSERT INTO EMPLOYEE VALUES (0001, '2020-02-29 00:00:00', '2021-02-28 00:00:00');
INSERT INTO EMPLOYEE VALUES (0002, '2019-03-01 00:00:00', '2021-02-28 00:00:00');

-- fetch 
SELECT empId, datediff(month, from_datetime, to_datetime) as months, datediff(day, from_datetime, to_datetime) as days FROM EMPLOYEE;
GO