Question

这是我正在使用的当前SQL查询：

SELECT Merchant.Product, Merchant.Name, Merchant.Price
FROM a_table AS Merchant
JOIN
(
SELECT Product, MIN(Price) AS MinPrice
FROM a_table
GROUP BY Product
) AS Price
ON Merchant.Product = Price.Product
AND Merchant.Price = Price.MinPrice

从这个数据集中：

Product    Name         Price   
11          Merch1      19.00   
11          Merch2      20.00
11          Merch3      19.00
11          Merch4      19.50
12          Merch1      20.00   
12          Merch2      20.00
13          Merch1      17.00
13          Merch3      15.00

当价格相同时，当前SQL会输出多个产品记录：

Product    Name         Price   
11          Merch1      19.00
11          Merch3      19.00   
12          Merch1      20.00
12          Merch2      20.00   
13          Merch3      15.00

我想按产品分组并显示最低价格和相应的行数据。如果产品上的两个价格相同，请使用找到的第一个记录。

试图得到这个结果：

Product    Name         Price   
11          Merch1      19.00   
12          Merch1      20.00   
13          Merch3      15.00

Answer 1

您不需要任何联接来执行此操作。

如果您希望商家获得每件商品的最低价格，您可以这样做：

SELECT Product, Name, MIN(Price) as MinPrice
FROM a_table
GROUP BY Product, Name

如果您只想要商品的最低价格而不管商家，您可以这样做：

SELECT Product, MIN(Price) as MinPrice
FROM a_table
GROUP BY Product

Answer 2

以下是最终符合我需求的查询...

http://sqlfiddle.com/#!9/c8937c/35/0

SELECT emp2.product,
       emp1.name,
       emp2.MinPrice
FROM (
  SELECT product,
     Min(price) as MinPrice
  FROM   Merchant
 GROUP BY product
) as emp2 JOIN Merchant as emp1 ON emp1.price = emp2.MinPrice
GROUP BY product;

MySQL组由min（）和限制输出组成

2 个答案: