Is there a way in Oracle SQL that I can look at a position of a column and determine if that data is an integer or not?

The column is defined as a varchar2 and I know I need to subscript into it(second position for 1 byte) but I don't know how to test for 0-9 without coding 0,1,2,3,4,5,6,7,8,9.

The data would look something like "CJE20020" and I want to include data with non-interger values(i.e. include the amount for this activity since the second position is a "J").