SQL NOT IN 查询

Question

谁能帮我解决这个 MySQL 查询？

SELECT p.ProductID, 
       p.StoreID, 
       p.DiscountPercentage 
 FROM Products p 
WHERE p.IsSpecial = 1 
  AND p.SpecialDate >= date_sub(now(),interval 15 minute) 
  AND p.DiscountPercentage >= ?DiscountPercentage 
  AND p.ProductID NOT IN (SELECT lf.LiveFeedID 
                            From LiveFeed lf 
                           WHERE p.ProductID = lf.ProductID 
                             AND lf.DateAdded >= date_sub(now(),interval 30 day)) 
  AND p.StoreID NOT IN (SELECT lf.LiveFeedID 
                          From LiveFeed lf 
                         WHERE p.StoreID = lf.StoreID 
                           AND lf.DateAdded >= date_sub(now(),interval 6 hour)) 
ORDER BY p.StoreID, p.DiscountPercentage DESC

我正在尝试加入过去 30 天内 ProductID 不在 livefeed 表中的位置，并且在过去 6 小时内 storeid 不在 livefeed 表中的位置，但它似乎不起作用。知道我做错了什么吗？

Answer 1

乍一看，您的第一个子查询应该选择ProductID，而不是LiveFeedID，而您的第二个子查询应该选择StoreID而不是LiveFeedID

Answer 2

我来晚了：

  SELECT p.ProductID, 
         p.StoreID, 
         p.DiscountPercentage 
    FROM Products p 
   WHERE p.IsSpecial = 1 
     AND p.SpecialDate >= date_sub(now(),interval 15 minute) 
     AND p.DiscountPercentage >= ?DiscountPercentage 
     AND p.ProductID NOT IN (SELECT lf.productid
                               FROM LIVEFEED lf
                              WHERE lf.DateAdded >= DATE_SUB(NOW(), INTERVAL 30 DAY)) 
     AND p.storeid NOT IN (SELECT lf.storeid
                             FROM LIVEFEED lf
                            WHERE lf.DateAdded >= DATE_SUB(NOW(), INTERVAL 6 HOUR)) 
ORDER BY p.StoreID, p.DiscountPercentage DESC

您正在使用 EXISTS 语法和相关子查询...

我正在尝试为每家商店获得最高折扣。

在这种情况下，使用：

  SELECT p.StoreID, 
         MAX(p.DiscountPercentage)
    FROM Products p 
   WHERE p.IsSpecial = 1 
     AND p.SpecialDate >= date_sub(now(),interval 15 minute) 
     AND p.DiscountPercentage >= ?DiscountPercentage 
     AND p.ProductID NOT IN (SELECT lf.productid
                               FROM LIVEFEED lf
                              WHERE lf.DateAdded >= DATE_SUB(NOW(), INTERVAL 30 DAY)) 
     AND p.storeid NOT IN (SELECT lf.storeid
                             FROM LIVEFEED lf
                            WHERE lf.DateAdded >= DATE_SUB(NOW(), INTERVAL 6 HOUR)) 
GROUP BY p.storeid
ORDER BY p.StoreID, p.DiscountPercentage DESC