SQLで再帰処理を行う

実装例

WITH regional_sales AS (

        SELECT region, SUM(amount) AS total_sales

        FROM orders

        GROUP BY region

     ), top_regions AS (

        SELECT region

        FROM regional_sales

        WHERE total_sales > (SELECT SUM(total_sales)/10 FROM regional_sales)

     )

SELECT region,

       product,

       SUM(quantity) AS product_units,

       SUM(amount) AS product_sales

FROM orders

WHERE region IN (SELECT region FROM top_regions)

GROUP BY region, product;

参考