Easiest mysql solution!!!!!!!!!!!!
\nselect employees.employee_id from employees left join salaries on\nemployees.employee_id=salaries.employee_id\nwhere salaries.employee_id is null \n\nunion\n\
```\nselect employees.employee_id from employees left join salaries on\nemployees.employee_id=salaries.employee_id\nwhere salaries.employee_id is null \n\nunion\n\nselect salaries.employee_id from salaries left join employees on\nemployees.employee_id=salaries.employee_id\nwhere employees.employee_id is null \n\norder by employee_id asc\n```
['Union Find', 'MySQL']