Simple MySQL Solution | 2 Approaches | Easy to understand | Faster than 99%
\n# Note: Full Outer Join is not supported by MySQL so we have to use left and right join with union in the below solution.\nselect employee_id from\n(select em
```\n# Note: Full Outer Join is not supported by MySQL so we have to use left and right join with union in the below solution.\nselect employee_id from\n(select emp.employee_id\nfrom employees emp left join salaries sal \non emp.employee_id = sal.employee_id\nwhere salary is null\nUNION\nselect sal.employee_id\nfrom employees emp right join salaries sal \non emp.employee_id = sal.employee_id\nwhere emp.name is null) temp\norder by employee_id\n\n# Faster Solution\nselect employee_id from\n(select employee_id from employees\nwhere employee_id NOT IN (select employee_id from salaries)\nUNION\nselect employee_id from salaries\nwhere employee_id NOT IN (select employee_id from employees)) temp\norder by employee_id\n\n# Do upvote if you like both the approaches\n```
['MySQL']