Simple and Easy MySQL Solutions (2 Approaches)
Approach 1\n\n#Using Join\nselect e.employee_id from Employees e\n    left join Salaries s on e.employee_id = s.employee_id\n    where s.salary is NULL    \nuni
Approach 1\n```\n#Using Join\nselect e.employee_id from Employees e\n    left join Salaries s on e.employee_id = s.employee_id\n    where s.salary is NULL    \nunion\nselect s.employee_id from Salaries s\n    left join Employees e on s.employee_id=e.employee_id\n    where e.name is NULL\norder by employee_id;\n \n```\n\nApproach 2\n```\nselect employee_id from Employees where employee_id not in(select employee_id from Salaries)\nunion\nselect employee_id from Salaries where employee_id not in (select employee_id from Employees)\norder by employee_id;\n```\n\n**Please UpVote if it was Helpful :)**
['MySQL']