使用两个表的内部联接的无效记录

Question

我有这个从codeigniter生成的sql语句

SELECT * FROM (`products`) LEFT JOIN `products_attributes` ON `products_attributes`.`product_id` = `products`.`id` WHERE `products`.`category` = '1' AND `products`.`sub_category` = '1' AND `products_attributes`.`attribute_id` = '3' AND `products_attributes`.`attribute_id` = '4' AND `products_attributes`.`attribute_id` = '5' GROUP BY `products`.`id`

我有这些表

产品： products_attributes：

我需要获得仅具有所有属性的产品，因此如果属性为3,4,5，我将获得产品id = 1，如果属性为3,4,5,6我将无法获得产品id = 1

Answer 1

您的SQL查询完全错误。你做的是： 给我记录的是attribute_id = 3 AND attribute_id = 4 AND attribute_id = 5 AND attribute_id = 6.一行不能同时等于3和4。 您需要的是以多种不同的方式实现的。例如：

SELECT
    products.id
FROM  products

    JOIN products_attributes ON products_attributes.product_id = products.id
WHERE
    products.category = '1'
    AND `products_attributes`.`attribute_id` IN (3,4,5,6)


GROUP BY
    products.id
HAVING COUNT(DISTINCT `products_attributes`.`attribute_id`) = 4

如果你只指定IN ...那么它将占用至少有1个这样的attribute_id

的所有记录

Answer 2

试试这个：

SELECT * FROM (`products`) 
LEFT JOIN `products_attributes` 
ON `products_attributes`.`product_id` = `products`.`id` 
WHERE `products`.`category` = 1 
AND `products`.`sub_category` = 1 
AND `products_attributes`.`attribute_id` IN (3, 4, 5) 
GROUP BY `products`.`id`