PLSQL - How to replicate a row changing columns first characters?

Question

I have a table with products like this:

PRODUCT_ID    SUB_PRODUCT_ID    DESCRIPTION   CLASS
----------    --------------    -----------   -----
A001        ACC1                coffeemaker   A
A002        ACC1                toaster       A
A003        ACC2                coffee table  A
A004        ACC5                couch         A

I need to replicate a row changing only first characters in some columns to get a result like this in the same table, for example if I take the first row I want to copy PRODUCT_ID changing only the first letter (from A001 to B001), SUB_PRODUCT_ID changing only the first letter (from ACC1 to BCC1), keep DESCRIPTION and change CLASS (from A to B)

PRODUCT_ID    SUB_PRODUCT_ID    DESCRIPTION   CLASS
----------    --------------    -----------   -----
A001          ACC1              coffeemaker   A
B001          BCC1              coffeemaker   B

I have been trying using SUBSTR function without positive results.

Answer 1

is this what you want?

insert into products(PRODUCT_ID, SUB_PRODUCT_ID, DESCRIPTION, CLASS)
    select replace(product_id, 'A', 'B'),
           replace(SUB_PRODUCT_ID, 'A', 'B'),
           DESCRIPTION,
           replace(CLASS, 'A', 'B')
    from products
    where class = 'A';

EDIT:

replace() might be overkill:

insert into products(PRODUCT_ID, SUB_PRODUCT_ID, DESCRIPTION, CLASS)
    select 'B' || substr(product_id, 2),
           'B' || substr(SUB_PRODUCT_ID, 2),
           DESCRIPTION,
           'B'
    from products
    where class = 'A';