# 181. Employees Earning More Than Their Managers

> Nguồn: https://tiennhm.io.vn/en/docs/leetcode/database/181-employees-earning-more-than-their-managers
> Write a solution to find the employees who earn more than their managers.

## Giới thiệu bài toán

Chi tiết: https://leetcode.com/problems/employees-earning-more-than-their-managers/

Table: `Employee`

| Column Name | Type    |
| ----------- | ------- |
| id          | int     |
| name        | varchar |
| salary      | int     |
| managerId   | int     |

- `id` is the primary key (column with unique values) for this table.
- Each row of this table indicates the ID of an employee, their name, salary, and the ID of their manager.

> **Tip: Yêu cầu**
>
> Write a solution to find the employees who earn more than their managers.
>
> Return the result table in any order. The result format is in the following example.
**Example 1:**

- Input: `Employee` table:

| id | name  | salary | managerId |
| -- | ----- | ------ | --------- |
| 1  | Joe   | 70000  | 3         |
| 2  | Henry | 80000  | 4         |
| 3  | Sam   | 60000  | Null      |
| 4  | Max   | 90000  | Null      |

- Output:

| Employee |
| -------- |
| Joe      |

- Explanation: Joe is the only employee who earns more than his manager.

## Giải quyết bài toán

```sql
SELECT e.name AS Employee
FROM Employee e
    INNER JOIN Employee m ON e.managerId = m.id
WHERE e.salary > m.salary;
```

Tham khảo: https://leetcode.com/submissions/detail/1039195164/