Question

我有3个表，商店，促销，store_promo_link

我想从商店中选择10行。商店必须每个都有1个特色促销，如果没有特色促销，那么选择最新的促销

CREATE TABLE IF NOT EXISTS `stores` (
  `StoreID` int(11) NOT NULL AUTO_INCREMENT,
  `StoreBranch` varchar(255) NOT NULL,
  `StoreName` varchar(255) NOT NULL,
  `IsFeatured` enum('0','1') NOT NULL DEFAULT '0',
  `OrderNumber` int(11) NOT NULL,
  PRIMARY KEY (`StoreID`),
  KEY `StoreBranch` (`StoreBranch`),
  FULLTEXT KEY `StoreDesc` (`StoreDesc`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=51 ;

CREATE TABLE IF NOT EXISTS `promos` (
  `PromoID` bigint(20) NOT NULL AUTO_INCREMENT,
  `Title` varchar(255) NOT NULL,
  `Description` text NOT NULL,
  `Photo` varchar(255) NOT NULL,
  `IsFeatured` enum('0','1') NOT NULL,
  `DateAdded` datetime NOT NULL,
  `DateUpdated` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`PromoID`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=36 ;


CREATE TABLE IF NOT EXISTS `store_promo_link` (
  `ID` bigint(20) NOT NULL AUTO_INCREMENT,
  `StoreID` int(11) NOT NULL,
  `PromoID` int(11) NOT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=149 ;

这是我的代码，但它从promos

返回第一行

SELECT s.StoreBranch, s.StoreName, s.StoreID , p.* FROM `stores` s
INNER JOIN store_promo_link sp ON s.StoreID = sp.StoreID
INNER JOIN (SELECT * FROM promos ORDER BY IsFeatured DESC, DateAdded DESC) p ON sp.PromoID = p.PromoID
GROUP BY sp.StoreID
ORDER BY OrderNumber = 0, OrderNumber, s.IsFeatured DESC LIMIT 10

修改我想选择10个独特的商店。每个商店都有多个促销。我只想为每家商店选择1个特色（IsFeature ='1'）促销。如果没有精选促销，则必须选择最新的促销。

谢谢！

Answer 1

您的查询工作正常。如果促销是特色你得到它，如果没有特色促销，你得到最后一个。请参阅我撰写的SQLFiddle。

没有商店重复：

StoreBranch     StoreName   StoreID     PromoID     Title   Description     Photo   IsFeatured  DateAdded   DateUpdated
be  ikea    1   2   2por1   promo2  foto2   1   September, 02 2015 00:00:00     September, 07 2015 10:48:54
es  mediamarkt  2   4   pollos  promo4  foto4   0   September, 04 2015 00:00:00     September, 07 2015 10:48:54

Mysql内连接命令第二个表

1 个答案: