Similar to SQL, you can use the [module operation](https://community.denodo.com/docs/html/browse/8.0/en/vdp/vql/functions/numeric_functions/numeric_functions#mod) (%) to set the limit or reset threshold of your generated sequence. Module operation or also called as modulo operator, returns the integer remainder when you perform division on 2 numbers.
To reset your ROW_NUMBER() counter every 100, you can write a query like below:
SELECT id, customer_name, 1 + ((ROW_NUMBER() OVER (ORDER BY id) - 1) % 100) AS rownum
Hope this helps!