在MySQL中联接三个表，并获得每个ID一行（第一个表中的每个实体一行）

Question

我有三个产品表，产品配置（例如，iPhone x 64黑色，iPhone x 64红色）和产品清单；我想选择所有产品，并按价格（在配置表中）和可用性（在库存表中）排序，但每个产品仅获得一行； id如何做到这一点？ 下面是我的mysql表结构

CREATE TABLE `product_inventories` (
  `inventory_id` bigint(20) NOT NULL,
  `quantity` int(11) NOT NULL,
  `warehouse_id` bigint(20) DEFAULT NULL,
  `config_id` bigint(20) NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8;

CREATE TABLE `product_configs` (
  `config_id` bigint(20) NOT NULL,
  `product_id` bigint(20) DEFAULT NULL,
  `price` decimal(12,3) DEFAULT NULL,
  `discount_percent` int(11) DEFAULT NULL,
  `sku` varchar(30) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8 ROW_FORMAT=FIXED;

CREATE TABLE `products` (
  `id` bigint(20) NOT NULL,
  `title` varchar(255) DEFAULT NULL,
  `category_id` bigint(20) NOT NULL,
) ENGINE=MyISAM DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC;

我尝试了此查询：

SELECT * 
FROM products 
    LEFT JOIN product_configs ON products.id = product_configs.product_id 
    LEFT JOIN product_inventories inventories ON inventories.inventory_id =
         (SELECT product_inventories.inventory_id from product_inventories
          WHERE product_inventories.config_id = product_configs.config_id
          ORDER by product_inventories.quantity DESC LIMIT 1 ) 
ORDER BY product_configs.price ASC, inventories.quantity DESC

修改： 与此查询：

SELECT *
FROM products 
    LEFT JOIN product_configs ON products.id = product_configs.product_id 
    LEFT JOIN product_inventories inventories ON inventories.inventory_id =
         (SELECT product_inventories.inventory_id from product_inventories
          WHERE product_inventories.config_idd = product_configs.config_id
          ORDER by product_inventories.quantity DESC LIMIT 1 ) 

ORDER BY product_configs.price is null, product_configs.price ASC, inventories.quantity DESC

我有以下结果；但是我想要每个配置一个产品的最小价格和最大数量

Answer 1

尝试一下：

SELECT 
    ...,
    SUM(quantity) AS total_quantity
FROM products AS p
    LEFT JOIN product_configs AS pc ON pc.product_id = p.id
    LEFT JOIN product_inventories AS pi ON pi.config_id = pc.config_id
GROUP BY p.id
ORDER BY pc.price ASC, pi.quantity DESC

Answer 2

尝试一下，看看是否可以使用：

SELECT *,MIN(price),MAX(quantity) FROM products LEFT JOIN product_configs ON products.id = product_configs.product_id LEFT JOIN product_inventories inventories ON inventories.inventory_id = (SELECT product_inventories.inventory_id FROM product_inventories INNER JOIN product_configs ON product_inventories.config_id = product_configs.config_id ORDER BY product_inventories.quantity DESC LIMIT 1 ) GROUP BY sku ORDER BY product_configs.price ASC, inventories.quantity DESC;

请注意，我仍然保留SELECT *，并在末尾添加了min(price),max(quantity)，以便进行比较。如果这对您不起作用，则可能需要提供一些数据示例，并说明所需输出的方式。