SQL Exclude Records with Leveling - sql

Question

For example, I have a table like this:
+---------+-------+----------+
| sort_id | level | security |
+---------+-------+----------+
| 1 | 1 | A |
| 2 | 2 | A |
| 3 | 3 | U |
| 4 | 4 | A |
| 5 | 5 | A |
| 6 | 3 | A |
| 7 | 4 | U |
| 8 | 5 | A |
| 9 | 6 | A |
| 10 | 7 | A |
| 11 | 3 | A |
| 12 | 3 | A |
+---------+-------+----------+
Security column is A for Authorized and U for Unauthorized. I need to exclude those records under the Unauthorized records based on their level.
For a better picture of the SQL records, it looks like this:
Those pointed with arrow are the Unauthorized records and we should exclude those under it.
So the SQL result should be the following table:
+---------+-------+----------+
| sort_id | level | security |
+---------+-------+----------+
| 1 | 1 | A |
| 2 | 2 | A |
| 3 | 3 | U |
| 6 | 3 | A |
| 7 | 4 | U |
| 11 | 3 | A |
| 12 | 3 | A |
+---------+-------+----------+
How can we produce it using a simple Select statement? Thanks in advanced! Just comment if something is unclear.

Answer 1

If I understand "under the unauthorized records" as meaning a sequence of records with increasing id`s following the unauthorized records (based on the id), then here is an approach:
select sort_id, level, security
from (select t.*, min(case when authorized = 'U' then id end) over (partition by grp) as minuid
from (select t.*,
(row_number() over (order by id) - level) as grp
from table t
) t
) t
where id > minuid;