SQL Taskbook Level 7.3
The tables are given:
| id | name | age |
|---|---|---|
| 1 | John | 32 |
| 2 | Mattew | 40 |
| 3 | Bill | 25 |
| 4 | Alex | 28 |
| 5 | Max | 34 |
| id | name | age | head_of_department_id |
|---|---|---|---|
| 1 | Andrew | 19 | 2 |
| 1 | Andrew | 19 | 2 |
| 2 | Julia | 25 | 3 |
| 3 | Karl | 26 | 5 |
| 4 | Donella | 28 | 5 |
| 5 | Barret | 29 | 1 |
| 6 | Alex | 32 | 4 |
| 7 | Donald | 33 | 3 |
| 8 | Brad | 20 | 4 |
| 9 | Omie | 21 | 3 |
| 10 | Mark | 22 | 1 |
Solve the following tasks for them:
Задание 1
Select all ages of superiors and subordinates.
Задание 2
Select all ages of superiors and subordinates only unique values.
Задание 3
Select bosses whose age is similar to the age of any subordinate.
Задание 4
Select the bosses whose age is greater than that of all their subordinates.
Задание 5
Select subordinates whose age is similar to the age of any boss.
Задание 6
Select subordinates whose age is less than that of all superiors.