https://leetcode.com/problems/employees-with-missing-information/description/


Success


```mysql
/*
(
SELECT Employees.employee_id FROM Employees
WHERE NOT EXISTS (SELECT Salaries.employee_id FROM Salaries WHERE Salaries.employee_id = Employees.employee_id)
UNION ALL
SELECT Salaries.employee_id FROM Salaries
WHERE NOT EXISTS (SELECT Employees.employee_id FROM Employees WHERE Employees.employee_id = Salaries.employee_id)
)
ORDER BY employee_id;
*/

(
SELECT Employees.employee_id AS employee_id FROM Employees
WHERE employee_id NOT IN (SELECT Salaries.employee_id FROM Salaries)
UNION ALL
SELECT Salaries.employee_id AS employee_id FROM Salaries
WHERE employee_id NOT IN (SELECT Employees.employee_id FROM Employees)
)
ORDER BY employee_id;
```