LeetCode in Kotlin

1965. Employees With Missing Information

Easy

SQL Schema

Table: Employees

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| employee_id | int     |
| name        | varchar |
+-------------+---------+
employee_id is the primary key for this table.
Each row of this table indicates the name of the employee whose ID is employee_id. 

Table: Salaries

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| employee_id | int     |
| salary      | int     |
+-------------+---------+
employee_id is the primary key for this table.
Each row of this table indicates the salary of the employee whose ID is employee_id. 

Write an SQL query to report the IDs of all the employees with missing information. The information of an employee is missing if:

Return the result table ordered by employee_id in ascending order.

The query result format is in the following example.

Example 1:

Input:

Employees table:

+-------------+----------+
| employee_id | name     |
+-------------+----------+
| 2           | Crew     |
| 4           | Haven    |
| 5           | Kristian |
+-------------+----------+

Salaries table:

+-------------+--------+
| employee_id | salary |
+-------------+--------+
| 5           | 76071  |
| 1           | 22517  |
| 4           | 63539  |
+-------------+--------+

Output:

+-------------+
| employee_id |
+-------------+
| 1           |
| 2           |
+-------------+

Explanation:

Employees 1, 2, 4, and 5 are working at this company.

The name of employee 1 is missing. The salary of employee 2 is missing.

Solution

# Write your MySQL query statement below
select employee_id
from employees
where employee_id not in (select employee_id from salaries)
UNION
select employee_id
from salaries
where employee_id not in (select employee_id from Employees)
order by 1