SQL 查询 - 每个类别、每个季度最畅销的产品

Question

I'm trying to write a query which will show the highest selling products, per category, per quarter.

The 'Product_Orders' table in the query has a field called 'Quantity' also, which will hold the number of orders, and I want to use this in the query to show the highest selling products per category, per quarter, so there would be a Quantity field in the final result of the query below, which I haven't added yet.

This is basically my query at the moment:

SELECT pc.category_name, pr.product_name, QUARTER(o.order_date) AS QUARTER
FROM Product pr
INNER JOIN Product_Category pc ON pr.category_code = pc.category_code
INNER JOIN Product_Orders po ON po.product_id = pr.product_id
INNER JOIN `Order` o ON o.order_id = po.order_id
WHERE pc.category_name IN ('Game','Console','Accessory')
AND o.order_date BETWEEN '2020-01-01' AND '2020-12-30'
Order BY o.order_date

As per the screenshot below, this obviously isn't working yet as intended:

I'm just wondering how do I go about writing this query so that it shows the highest selling for each category and for each quarter eg Q1,Q2,Q3,Q4 for Game, Q1,Q2,Q3,Q4 for Console

CREATE TABLE syntax for tables used:

CREATE TABLE `Product_Category` (
  `category_code` int(11) NOT NULL AUTO_INCREMENT,
  `category_name` varchar(50) NOT NULL,
  `category_description` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`category_code`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=latin1;

CREATE TABLE `Product` (
  `product_id` int(11) NOT NULL AUTO_INCREMENT,
  `product_name` varchar(50) NOT NULL,
  `product_description` varchar(255) DEFAULT NULL,
  `retail_price` decimal(10,0) NOT NULL,
  `category_code` int(11) NOT NULL,
  PRIMARY KEY (`product_id`),
  KEY `category_code` (`category_code`),
  CONSTRAINT `Product_ibfk_1` FOREIGN KEY (`category_code`) REFERENCES `Product_Category` (`category_code`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1;

CREATE TABLE `Order` (
  `order_id` int(11) NOT NULL AUTO_INCREMENT,
  `order_date` date NOT NULL,
  `transaction_amount` decimal(10,0) NOT NULL,
  `shipping_address_id` int(11) NOT NULL,
  `billing_address_id` int(11) NOT NULL,
  `customer_id` int(11) NOT NULL,
  PRIMARY KEY (`order_id`),
  KEY `shipping_address_id` (`shipping_address_id`),
  KEY `billing_address_id` (`billing_address_id`),
  KEY `customer_id` (`customer_id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=latin1;

CREATE TABLE `Product_Orders` (
  `order_id` int(11) NOT NULL AUTO_INCREMENT,
  `product_id` int(11) NOT NULL,
  `quantity` int(11) NOT NULL,
  `selling_price` decimal(10,0) NOT NULL,
  PRIMARY KEY (`order_id`,`product_id`),
  KEY `product_id` (`product_id`),
  CONSTRAINT `Product_Orders_ibfk_1` FOREIGN KEY (`order_id`) REFERENCES `Order` (`order_id`),
  CONSTRAINT `Product_Orders_ibfk_2` FOREIGN KEY (`product_id`) REFERENCES `Product` (`product_id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=latin1;

INSERTS for tables:

INSERT INTO `Product_Category` VALUES 
(1, 'Game', 'Disc-based and cartridge-based media'),
(2, 'Console', 'Game platforms such as Nintento, Playstation and Xbox');

INSERT INTO `Product` VALUES 
(1, 'Metal Gear Solid', 'Game developed by Kojima Productions', 50, 1),
(2, 'Nintendo Switch', 'Nintendo games console', 250, 2),
(3, 'Tekken 7', 'Fighting game developed by NAMCO', 50, 1),
(4, 'Zelda', 'Nintendo Game', 70, 1);

INSERT INTO `Order` VALUES 
(1, '2020-10-10', 50, 1, 1, 1),(2, '2020-01-20', 250, 1, 1, 1),
(3, '2020-01-05', 40, 1, 1, 1),(4, '2020-01-24', 70, 1, 1, 1),
(5, '2020-01-06', 50, 1, 1, 1);

INSERT INTO `Product_Orders` VALUES 
(1, 1, 1, 30),(2, 2, 1, 220),
(3, 3, 1, 25),(4, 4, 1, 70),(5, 1, 5, 50);

Answer 1

Perhaps, like this:

SELECT pc.category_name, pr.product_name, QUARTER(o.order_date) AS QUARTER, po.Quantity
  FROM Product pr
  INNER JOIN Product_Category pc ON pr.category_code = pc.category_code
  INNER JOIN Product_Orders po ON po.product_id = pr.product_id
  INNER JOIN `Order` o ON o.order_id = po.order_id
 WHERE pc.category_name IN ('Game','Console','Accessory')
  AND o.order_date BETWEEN '2020-01-01' AND '2020-12-30'
Order BY category_name, QUARTER(order_date), Quantity DESC

I've added po.quantity in SELECT and change the ORDER BY code. One thing I notice you're doing AND o.order_date BETWEEN '2020-01-01' AND '2020-12-30' , isn't it suppose to be until '2020-12-31' ? Also, there's a few variation of filtering date you can do other than BETWEEN . If you're only looking for year 2020 data, you can simply do AND o.order_date LIKE '2020%' or AND YEAR(o.order_date)='2020' but as far as I know, the latter (using YEAR() ) doesn't make use of (if there's an) index on o.order_date column.

Here's a demo fiddle inclusive of a few other variation of queries.