Calculate total revenue in each category for every week in 2021. (‘order_date’ field is a timestamp value) use practice; SELECT sum(order_detail.Revenue),item_detail.cateogory,customer_id,week(customers_orders.order_date) FROM order_detail JOIN item_detail on order_detail.Item_id=item_detail.Item_id join customers_orders on customers_orders.order_id=order_detail.order_id where year(customers_orders.order_date)>'2020' group by item_detail.cateogory,yearweek(customers_orders.order_date);