i have acheived similar result specfying OR condition with where clause, is that ok?

SELECT 
    *
FROM
    (SELECT 
        t1.emp_no AS emp,
            t2.dept_no AS dept,
            (SELECT 
                    emp_no
                FROM
                    dept_manager
                WHERE
                    emp_no = 110022) AS manager
    FROM
        employees AS t1
    JOIN dept_emp AS t2 ON t1.emp_no = t2.emp_no
    WHERE
        t1.emp_no <= 10020
            OR t1.emp_no = '110039'
    GROUP BY t1.emp_no , t2.dept_no
    ORDER BY emp) AS A 
UNION SELECT 
    *
FROM
    (SELECT 
        t1.emp_no AS emp,
            t2.dept_no AS dept,
            (SELECT 
                    emp_no
                FROM
                    dept_manager
                WHERE
                    emp_no = 110039) AS manager
    FROM
        employees AS t1
    JOIN dept_emp AS t2 ON t1.emp_no = t2.emp_no
    WHERE
        t1.emp_no BETWEEN '10021' AND '10040'
            OR t1.emp_no = '110022'
    GROUP BY t1.emp_no , t2.dept_no
    ORDER BY emp) AS b
ORDER BY emp;