Oracle paging greater than or equal to less than paging critical point

If the oracle paging value is greater than or equal to the paging critical point, the SQL code SELECT * FROM (SELECT. *, rownum rn from (select * from t_agent t where t. agent_parent = 20020 and t. agent_state = 0) a where rownum <= 22) where rn> 0; Incorrect: only 21 data records are retrieved to the critical point. For example, 22 data records exist, the next page does not display a piece of data. Only one page is displayed, and 21 pieces of data are missing. SQL code SELECT * FROM (SELECT. *, rownum rn from (select * from t_agent t where t. agent_parent = 20020 and t. agent_state = 0) a where rownum <22) where rn> = 0;