Task: Text to Code
Input (English): Step 1: For each row in Product_Categories table, find the corresponding rows in Products table.
Step 2: find each value of parent_product_id in the results of step 1 along with the summation of vat_rating of the corresponding rows to each value
Output (English): SELECT T2.parent_product_id , Sum ( T1.vat_rating ) FROM Product_Categories AS T1 JOIN Products AS T2 ON T1.production_type_code = T2.production_type_code GROUP BY T2.parent_product_id