DELETE

DELETE
FROM
    employees2
WHERE
    deparment_id = 90;

DELETE
FROM
    (
        SELECT
            *
        FROM
            employees2
        WHERE
            department_id = 90
    );

DELETE
FROM
    employees2
WHERE
    department_id IN (
        SELECT
            department_id
        FROM
            departments
        WHERE
            department_name = 'Executive';