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我要求在产品详细信息页面中显示类似产品，以便列出的产品应以分层方式与当前产品属性匹配，如下所示

  1. 尺寸、颜色、类别、公司应与当前产品匹配
  2. 尺寸、颜色、类别应与当前产品匹配
  3. 尺寸、颜色应与当前产品相匹配
  4. 尺寸应与当前产品匹配

我的 sql 查询如下所示：

(SELECT pd.product_id, pd.name, p.price 
        FROM mg_product_description pd 
            JOIN `mg_product` p ON p.product_id = pd.product_id 
        WHERE 
            pd.size_id = '33' AND 
            pd.color_id = '2' AND 
            pd.category_id = '3' AND 
            pd.company_id = '1'  AND 
            pd.product_id != '53'  AND 
            p.status = '1' 
            ORDER BY RAND() LIMIT 10 
    )
        UNION
    (SELECT pd.product_id, pd.name, p.price 
        FROM mg_product_description pd 
            JOIN `mg_product` p ON p.product_id = pd.product_id 
        WHERE 
            pd.size_id = '33' AND 
            pd.color_id = '2' AND 
            pd.category_id = '3'  AND 
            pd.product_id != '53'  AND 
            p.status = '1' 
            ORDER BY RAND() LIMIT 10 
    )
        UNION
    (SELECT pd.product_id, pd.name, p.price 
        FROM mg_product_description pd 
            JOIN `mg_product` p ON p.product_id = pd.product_id 
        WHERE 
            pd.size_id = '33' AND 
            pd.color_id = '2' AND 
            pd.product_id != '53'  AND 
            p.status = '1' 
            ORDER BY RAND() LIMIT 10 
    )
        UNION
    (SELECT pd.product_id, pd.name, p.price 
        FROM mg_product_description pd 
            JOIN `mg_product` p ON p.product_id = pd.product_id 
        WHERE 
            pd.size_id = '33' AND 
            pd.product_id != '53' AND 
            p.status = '1'
            ORDER BY RAND() LIMIT 10 
    )

53 - 当前产品 ID 和状态表示可用！

有没有办法优化上述查询？

注意 需要输出：我们需要 10 个类似的产品。如果有 4 个符合条件 1 的产品，则需要先随机列出。同样，我们需要在其下方列出符合其他条件的产品。

提前致谢！

4

1 回答 1

1

Keeping using ORDER BY RAND() (which is not efficient) then a very basic improvement would be to add a priority for each clause, move the order clause to the end so it is only needed once.

(SELECT pd.product_id, pd.name, p.price , 1 AS recpriority
        FROM mg_product_description pd 
            JOIN `mg_product` p ON p.product_id = pd.product_id 
        WHERE 
            pd.size_id = '33' AND 
            pd.color_id = '2' AND 
            pd.category_id = '3' AND 
            pd.company_id = '1'  AND 
            pd.product_id != '53'  AND 
            p.status = '1' 
    )
        UNION
    (SELECT pd.product_id, pd.name, p.price , 2 AS recpriority
        FROM mg_product_description pd 
            JOIN `mg_product` p ON p.product_id = pd.product_id 
        WHERE 
            pd.size_id = '33' AND 
            pd.color_id = '2' AND 
            pd.category_id = '3'  AND 
            pd.product_id != '53'  AND 
            p.status = '1' 
    )
        UNION
    (SELECT pd.product_id, pd.name, p.price , 3 AS recpriority
        FROM mg_product_description pd 
            JOIN `mg_product` p ON p.product_id = pd.product_id 
        WHERE 
            pd.size_id = '33' AND 
            pd.color_id = '2' AND 
            pd.product_id != '53'  AND 
            p.status = '1' 
    )
        UNION
    (SELECT pd.product_id, pd.name, p.price , 4 AS recpriority
        FROM mg_product_description pd 
            JOIN `mg_product` p ON p.product_id = pd.product_id 
        WHERE 
            pd.size_id = '33' AND 
            pd.product_id != '53' AND 
            p.status = '1'
    )
    ORDER BY recpriority, RAND() LIMIT 10

That could then be done without the need for unions by doing something like this:-

SELECT pd.product_id, 
    pd.name, 
    p.price , 
    CASE
        WHEN pd.color_id = '2' AND pd.category_id = '3' AND pd.company_id = '1'  THEN 1 
        WHEN pd.color_id = '2' AND pd.category_id = '3' THEN 2 
        WHEN pd.color_id = '2' THEN 3 
        ELSE 4 
    END AS recpriority
FROM mg_product_description pd 
JOIN `mg_product` p ON p.product_id = pd.product_id 
WHERE pd.size_id = '33' 
AND pd.product_id != '53' 
AND p.status = '1'
ORDER BY recpriority, RAND() 
LIMIT 10
于 2013-07-09T09:32:50.053 回答