MySQL - Group by price range

SELECT price_range, count(*) AS num
FROM
(SELECT CASE WHEN product_price >= 150 AND product_price <= 249.99 THEN '150-249.99'
             WHEN product_price >= 250 AND product_price <= 299.99 THEN '250-299.99'
             WHEN product_price >= 300 AND product_price <= 399.99 THEN '300-399.99'
             WHEN product_price >= 400 AND product_price <= 499.99 THEN '400-499.99'
             WHEN product_price >= 500 AND product_price <= 999.99 THEN '500-999.99'
             ELSE 'over 1000'
         END as price_range
FROM washing_machines
WHERE 1
) AS  price_summaries
GROUP BY price_range