1. 

Take the two products with the lowest prices in the table.
OR take two products with the lowest prices in every category. 

Increase their price with the "price rate" of the category: which is 15% of the difference between the biggest and the smallest price in a category.

(HOMEWORK: do the same with all products that have the two lowest prices in every category)

2. 

Use recursive CTE to display the hierarchy of workers! Then use recursive CTE to display the hierarchy of product main+sub categories