# $1767. 寻找没有被执行的任务对
# https://leetcode-cn.com/problems/find-the-subtasks-that-did-not-execute/

# SQL架构
Create table If Not Exists Tasks (task_id int, subtasks_count int);
Create table If Not Exists Executed (task_id int, subtask_id int);
Truncate table Tasks;
insert into Tasks (task_id, subtasks_count) values ('1', '3');
insert into Tasks (task_id, subtasks_count) values ('2', '2');
insert into Tasks (task_id, subtasks_count) values ('3', '4');
Truncate table Executed;
insert into Executed (task_id, subtask_id) values ('1', '2');
insert into Executed (task_id, subtask_id) values ('3', '1');
insert into Executed (task_id, subtask_id) values ('3', '2');
insert into Executed (task_id, subtask_id) values ('3', '3');
insert into Executed (task_id, subtask_id) values ('3', '4');

# Write your MySQL query statement below
with recursive tmp(task_id, subtask_id) as (
    select
        task_id,
        subtasks_count
    from
        Tasks
    union
    select
        task_id,
        (subtask_id -1) as subtasks_count
    from
        tmp
    where
        subtask_id >= 2
)
select
    task_id,
    subtask_id
from
    tmp
where
    (task_id, subtask_id) not in (
        select
            task_id,
            subtask_id
        from
            Executed
    );

# clean-up
drop table Tasks;
drop table Executed;