Oracle SQL Find max digit in number in cell

Question

I have a column like that :

How can I find the max digit column? ( I want to select the max digit from the left column and write it to a new column)

WITH ORACLE SQL

THANKS!!!

Answer 1

Solving it like a pro:

Creating sample data:

CREATE TABLE tab as
WITH t(col) AS
(
 SELECT 134425  FROM dual UNION ALL
 SELECT 6453356 FROM dual UNION ALL
 SELECT 65267   FROM dual UNION ALL
 SELECT 9999    FROM dual UNION ALL
 SELECT 467533  FROM dual
)
SELECT * FROM t;

Solution:

select * from tab,
lateral
( 
    select max(substr(col, level, 1)) max_digit
    from   dual
    connect by level <= length(col)
)

Output: