MYSQL分段统计

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;