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使用 SQL MIN() 函数时，我想选择与 MIN 行匹配的任何其他字段。以下查询返回正确的 MIN(sellPrice)，但与 product_price 表中的正确行不匹配。我怎样才能做到这一点？

SELECT p.*, MIN(pp.sellPrice) AS sellPrice, pp.* FROM `product` AS p
LEFT JOIN `product_price_group` AS ppg ON p.`id` = ppg.`productId`
LEFT JOIN `product_price` AS pp ON ppg.`id` = pp.`priceGroupId`
WHERE p.`active` = 1 AND p.id = 1
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3 回答 3

1

您正在寻找的是没有更低价格的所有行：

SELECT p.*, pp.sellPrice AS sellPrice, pp.* FROM `product` AS p
LEFT JOIN `product_price_group` AS ppg ON p.`id` = ppg.`productId`
LEFT JOIN `product_price` AS pp ON ppg.`id` = pp.`priceGroupId`
WHERE p.`active` = 1 AND p.id = 1
   AND NOT EXISTS (SELECT 1 FROM product_price AS pp2
       WHERE pp2.productId = pp.productId AND pp2.sellPrice < pp.sellPrice)
GROUP BY productId;

我猜测涉及哪些键。这个想法是WHERE NOT EXISTS寻找价格较低的任何相关行。这样，MySQL 将在您的结果中仅包含无法找到此类“较低价格”匹配的行。

于 2011-04-13T21:01:07.663 回答
1

您想要所有产品或每种产品的最低销售价格吗？

适用于所有产品

SELECT p.*
     , pp.sellPrice
     , pp.*
FROM product AS p
LEFT JOIN product_price_group AS ppg
  ON p.id = ppg.productId
LEFT JOIN product_price AS pp
  ON ppg.id = pp.priceGroupId
WHERE p.active = 1
  AND p.id = 1
  AND pp.sellPrice =
    ( SELECT MIN(pp.sellPrice)
      FROM product_price
    )

对于每一个产品

SELECT p.*
     , pp.sellPrice
     , pp.*
FROM product AS p
LEFT JOIN product_price_group AS ppg
  ON p.id = ppg.productId
LEFT JOIN product_price AS pp
  ON ppg.id = pp.priceGroupId
JOIN
  ( SELECT priceGroupId
         , pp.MIN(pp.sellPrice) AS sellPrice
    FROM product_price
    GROUP BY priceGroupId
  ) AS ppmin
  ON  ppmin.priceGroupId = pp.priceGroupId
  AND ppmin.sellPrice = sellPrice
WHERE p.active = 1
  AND p.id = 1
于 2011-04-13T22:15:44.393 回答
1

根据一些建议，我使用了 GROUP BY 属性，如果我想要某个产品的最低销售价格，则以下查询可以正常工作：

SELECT p.*, MIN(pp.sellPrice) AS sellPrice, pp.quantity, pp.`priceGroupId`
FROM `product` AS p
LEFT JOIN `product_price_group` AS ppg ON ppg.productId = p.`id`
LEFT JOIN `product_price` AS pp ON pp.priceGroupId = ppg.`id`
WHERE p.`active` = 1 AND  p.id = 1 AND pp.sellPrice IS NOT NULL
GROUP BY pp.id;

对于所有产品：

SELECT p.*, MIN(pp.sellPrice) AS sellPrice, pp.quantity, pp.`priceGroupId`
FROM `product` AS p
LEFT JOIN `product_price_group` AS ppg ON ppg.productId = p.`id`
LEFT JOIN `product_price` AS pp ON pp.priceGroupId = ppg.`id`
WHERE p.`active` = 1 AND pp.sellPrice IS NOT NULL
GROUP BY pp.id;
于 2011-04-14T07:33:19.977 回答