#坑在于输出的名字顺序要按照employee表存储的顺序来输出，需要在where再加一层子查询
select e.first_name
FROM employees e
where e.emp_no in
(select a.emp_no
FROM
(SELECT * , row_number() OVER( ORDER by first_name ) as row
from employees) as a
WHERE a.row%2!=0)