WITH    temp_table AS
        (SELECT  TO_DATE('01-JAN-2020', 'DD-MON-YYYY')  start_with_date
                ,DATEADD('Days', 0, start_with_date)    start_date
                ,DATEADD('Days', 1, start_with_date)    end_date
                ,1                                      level
         FROM   dual
        )
SELECT   DATEADD('Days', level, start_date) n_start_date
        ,DATEADD('Days', level, end_date)   n_end_date
        ,start_date
        ,end_date
        ,(level +1) AS level
FROM    temp_table
START WITH start_date = TO_DATE('01-JAN-2020', 'DD-MON-YYYY')
CONNECT BY
        start_date + LEVEL      >= PRIOR end_date
AND     end_date        < TO_DATE('01-JAN-2021', 'DD-MON-YYYY')
LIMIT 25
;