如果项目具有许多(动态)属性,则多个左连接

时间:2013-09-23 12:52:44

标签: php mysql sql

我有两个表,产品和属性。每个产品都有很多属性!

当我必须找到具有多个pattributes的产品时,问题就开始了。

select * from `products` 
left join `pattributes` on `pattributes`.`products_id` = `products`.`id` 
where `products`.`status` = 1 
AND `products`.`sold` = 0 
AND `products`.`deleted` = 0 
AND `products`.`categories_id` = 30 
AND `pattributes`.`attributes_id` = 5 
AND `pattributes`.`values_id` = 10 
AND `pattributes`.`attributes_id` = 4 
AND `pattributes`.`values_id` = 15 
group by `products`.`id` 
order by `products`.`top` desc, 
`products`.`id` desc

因此,如果我正在寻找两个或更多的pattributes,它返回0行。但是,如果我寻找一个pattribute它可以正常工作。

我不是一个mysql大师,不确定我是否必须使用左连接。也许有人知道它的最佳解决方案?

添加了SQL小提琴 - 可能会更容易http://sqlfiddle.com/#!2/b3ada0

2 个答案:

答案 0 :(得分:0)

IN()用于多个pattributes,与多个values_id

相同
select * from `products` 
left join `pattributes` on `pattributes`.`products_id` = `products`.`id` 
where `products`.`status` = 1 
AND `products`.`sold` = 0 
AND `products`.`deleted` = 0 
AND `products`.`categories_id` = 30 
AND `pattributes`.`attributes_id` IN(5 ,4)// if type is varchar then IN('5' ,'4')
AND `pattributes`.`values_id` IN( 10,15 )
group by `products`.`id` 
order by `products`.`top` desc, 
`products`.`id` desc

答案 1 :(得分:0)

最后,有些朋友帮忙搞定了:

SELECT 
    * 
FROM 
    `products`
WHERE 
    `products`.`status` = 1 
    AND `products`.`sold` = 0 
    AND `products`.`deleted` = 0 
    AND `products`.`categories_id` = 30
    AND 
    (
        (SELECT 
             COUNT(*) 
         FROM `pattributes`
         WHERE 
             `pattributes`.`products_id` = `products`.`id`
             AND 
             (
                 (
                   `pattributes`.`attributes_id` = 4
                   AND `pattributes`.`values_id` = 14
                 )
                 OR
                 (
                   `pattributes`.`attributes_id` = 5
                   AND `pattributes`.`values_id` = 10
                 )
             )
         ) = 2

    )
GROUP BY `products`.`id`
ORDER BY `products`.`top` DESC, `products`.`id` DESC