select * from employees where SUBSTRING(emp_no,5,1) in ('1','3','5','7','9') and last_name != 'Mary' order by hire_date DESC

SUBSTRING 解题思路:

1.本题需要获取emp_no为奇数的员工信息,只要判断出emp_no为奇数就可以,此处采用substring截取末位字符进行判断; 2.相比于取余运算进行判断,这个稍微麻烦点