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为商店构建报告并尝试按制造商 ID 获取类别。做 MySQL 查询不走运（经验几乎为零，呵呵），但我有这个：

制造商-产品-product_category-category-category_description

表架构

CREATE SCHEMA IF NOT EXISTS `table` DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci ;
USE `table` ;

-- -----------------------------------------------------
-- Table `table`.`category_description`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `table`.`category_description` (
  `category_id` INT(11) NOT NULL AUTO_INCREMENT ,
  `name` VARCHAR(45) NOT NULL ,
  PRIMARY KEY (`category_id`) )
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `table`.`category`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `table`.`category` (
  `category_id` INT(11) NOT NULL AUTO_INCREMENT ,
  `image` VARCHAR(255) NULL ,
  PRIMARY KEY (`category_id`) )
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `table`.`manufacturer`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `table`.`manufacturer` (
  `manufacturer_id` INT(11) NOT NULL AUTO_INCREMENT ,
  `name` VARCHAR(64) NOT NULL DEFAULT '' ,
  PRIMARY KEY (`manufacturer_id`) )
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `table`.`product`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `table`.`product` (
  `product_id` INT(11) NOT NULL AUTO_INCREMENT ,
  `manufacturer_id` INT(11) NOT NULL ,
  `name` VARCHAR(45) NULL ,
  PRIMARY KEY (`product_id`) ,
  INDEX `product_manufacturer` (`manufacturer_id` ASC) )
ENGINE = InnoDB;


-- -----------------------------------------------------
-- Table `table`.`product_category`
-- -----------------------------------------------------
CREATE  TABLE IF NOT EXISTS `table`.`product_category` (
  `product_id` INT(11) NOT NULL ,
  `category_id` INT(11) NOT NULL ,
  PRIMARY KEY (`product_id`, `category_id`) ,
  INDEX `product_to_category_product_id` (`product_id` ASC) ,
  INDEX `product_to_category_category_id` (`category_id` ASC) )
ENGINE = InnoDB;

-- Sorry if example data is not provided

MySQL 查询

SELECT category_description.name, category.category_id
FROM manufacturer
  JOIN product ON product.manufacturer_id = manufacturer.manufacturer_id
  JOIN product_to_category ON product_to_category.product_id = product.product_id
  JOIN category ON category.category_id = product_to_category.category_id
  JOIN category_description ON category_description.category_id = category.category_id
  WHERE manufacturer.manufacturer_id = 7

查询结果有很多category_description.name重复的行（我猜是继承自我的新手查询）

架构基于产品，而是选择制造商的想法，那么获得与其产品相关的所有类别都获得（独特）。

由于缺乏构建查询的知识，我有货

编辑：很抱歉，更正了category表行名称（category.image改为category.name）

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1 回答 1

1

给你（sqlfiddle）：

SELECT DISTINCT category_description.name, category.category_id
FROM product
  JOIN product_category ON product_category.product_id = product.product_id
  JOIN category ON category.category_id = product_category.category_id
  JOIN category_description ON category_description.category_id = category.category_id
  WHERE product.manufacturer_id = 1

a) 不要链接你不需要的表

b) 用于DISTINCT清理被剪断的曾经不同的数据（即产品，此处）生成的欺骗。

c）不要拼错表名：p

于 2012-12-10T06:04:42.377 回答