15.查找employees表所有emp_no为奇数

查找employees表所有emp_no为奇数，且last_name不为Mary的员工信息，并按照hire_date逆序排列

CREATE TABLE `employees` (
`emp_no` int(11) NOT NULL,
`birth_date` date NOT NULL,
`first_name` varchar(14) NOT NULL,
`last_name` varchar(16) NOT NULL,
`gender` char(1) NOT NULL,
`hire_date` date NOT NULL,
PRIMARY KEY (`emp_no`));

解析：奇数条件是考察重点

select * 
from employees
where emp_no&1
and last_name != 'Mary'
order by hire_date desc;