Can a database table contain one column?

Question

MySQL

Task - table with task data.
Block_task - task numbers that are displayed at the beginning of testing.
After the presentation of the initial block of tasks, the order of the questions changes.
Is it possible to leave the DB structure like this? Or can it be done in some other way?

Answer 1

Yes.
Yes.
Another way is also possible. For example, bool field is_start in task.