-- 新規追加時用。
INSERT IGNORE INTO
dtb_category_count 
SELECT
	category_id,
	0 as product_count,
	NOW() as create_date
FROM
	dtb_category;

-- まとめて更新用	
UPDATE
	dtb_category_count
SET
	product_count = COALESCE(
	(
		SELECT
			COUNT(*) 
		FROM
			dtb_product_categories AS T2 
		WHERE
			category_id = dtb_category_count.category_id AND
			EXISTS(
				SELECT
					*
				FROM
					dtb_products
				WHERE
					product_id = T2.product_id AND
					del_flg = 0 AND 
					status = 1
			
			)
	),0);