产品表
CREATE TABLE `product` (
`product_id` int(11) NOT NULL AUTO_INCREMENT,
`product_model` varchar(255) NOT NULL,
`product_price` decimal(15,4) NOT NULL,
`product_status` tinyint(1) unsigned NOT NULL,
`product_add_time` int(11) unsigned DEFAULT '0',
PRIMARY KEY (`product_id`),
KEY `product_price` (`product_price`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=utf-8
分类表
CREATE TABLE `category` (
`category_id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`category_name` varchar(255) NOT NULL,
PRIMARY KEY (`category_id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf-8
产品分类表
CREATE TABLE `product_to_category` (
`product_id` int(11) unsigned NOT NULL,
`category_id` int(11) unsigned NOT NULL,
PRIMARY KEY (`product_id`,`category_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf-8
要获取产品价格区间统计上架的Shoes类别的产品，状态为在售停售的数目
SELECT
sum(CASE when product.product_price<10 then 1 else 0 end) AS '(0,10)',
sum(CASE when product.product_price>=10 and product.product_price<20 then 1 else 0 end) AS '[10,20)',
sum(CASE when product.product_price>=20 and product.product_price<30 then 1 else 0 end) AS '[20,30)',
sum(CASE when product.product_price>=30 and product.product_price<40 then 1 else 0 end) AS '[30,40)',
sum(CASE when product.product_price>=40 then 1 else 0 end) AS '[40,+)'
FROM test.product AS product
LEFT JOIN test.product_to_category map ON product.product_id = map.product_id
LEFT JOIN test.category category ON map.category_id = category.category_id
WHERE category.category_name = 'Shoes' group by product.product_status;