1767. Find the Subtasks That Did Not Execute

https://leetcode.com/problems/find-the-subtasks-that-did-not-execute

Description

Table: Tasks

+----------------+---------+
| Column Name    | Type    |
+----------------+---------+
| task\_id        | int     |
| subtasks\_count | int     |
+----------------+---------+
task\_id is the primary key for this table.
Each row in this table indicates that task\_id was divided into subtasks\_count subtasks labelled from 1 to subtasks\_count.
It is guaranteed that 2 <= subtasks\_count <= 20.

Table: Executed

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| task\_id       | int     |
| subtask\_id    | int     |
+---------------+---------+
(task\_id, subtask\_id) is the primary key for this table.
Each row in this table indicates that for the task task\_id, the subtask with ID subtask\_id was executed successfully.
It is **guaranteed** that subtask\_id <= subtasks\_count for each task\_id.

Write an SQL query to report the IDs of the missing subtasks for each task_id.

Return the result table in any order.

The query result format is in the following example:

Tasks table:
+---------+----------------+
| task\_id | subtasks\_count |
+---------+----------------+
| 1       | 3              |
| 2       | 2              |
| 3       | 4              |
+---------+----------------+
Executed table:
+---------+------------+
| task\_id | subtask\_id |
+---------+------------+
| 1       | 2          |
| 3       | 1          |
| 3       | 2          |
| 3       | 3          |
| 3       | 4          |
+---------+------------+
Result table:
+---------+------------+
| task\_id | subtask\_id |
+---------+------------+
| 1       | 1          |
| 1       | 3          |
| 2       | 1          |
| 2       | 2          |
+---------+------------+
Task 1 was divided into 3 subtasks (1, 2, 3). Only subtask 2 was executed successfully, so we include (1, 1) and (1, 3) in the answer.
Task 2 was divided into 2 subtasks (1, 2). No subtask was executed successfully, so we include (2, 1) and (2, 2) in the answer.
Task 3 was divided into 4 subtasks (1, 2, 3, 4). All of the subtasks were executed successfully.

ac