mysql - 我需要加入吗？

Question

我有 3 个表:products、products_description、products_to_categories

这是我的 sql:

SELECT `products`.`products_model`, 
       `products_description`.`products_name` 
FROM   products, 
       products_description, 
       products_to_categories 
WHERE  `products`.`products_id` = `products_description`.`products_id` = 
                                         `products_to_categories`. `products_id` 
       AND `products_to_categories`.`categories_id` <> '91' 
ORDER  BY `products`.`products_model` DESC 

所有三个表都以 products_id 作为主键，我试图基于此链接所有三个表。我想我需要一个连接，因为我似乎无法在一个语句中使所有三个都相等？

Answer 1

您可以使用 JOIN 来实现，但如果您想使用 Where 语句也可以，但您必须使用 AND 才能实现

SELECT `products`.`products_model`, `products_description`.`products_name`
FROM products, products_description, products_to_categories
WHERE `products`.`products_id` =  `products_description`.`products_id` 
   AND `products`.`products_id`= `products_to_categories`.`products_id` 
   AND `products_to_categories`.`categories_id` <> '91' 
ORDER BY `products`.`products_model` DESC