本文介绍了如何在sql中使用GroupBy?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧! 问题描述 我有这样的表格 Id ProductName MainCategory AdditionalCategory size 1 美国烤咖啡 10 2 美国烤咖啡 12 3 美国烤咖啡 14 4 美国烤咖啡 16 5 美国烤咖啡夏威夷 10 6 美国烤咖啡夏威夷 12 7 美国烤咖啡夏威夷 14 8 美国烤咖啡夏威夷 16 9 美国烤咖啡Kona 10 10 美国烤咖啡Kona 12 11 American Roast Coffee Kona 14 12 American Roast Coffee Kona 16 我在这个表中逐个使用 选择 Productname,Maincategory,AdditionalCategory1 来自 testproducts group by Productname,Main category,AdditionalCategory1 我得到了这样的结果 ProductName MainCategory AdditionalCategory 美国烤咖啡美国烤咖啡夏威夷美国烤咖啡Kona 但是我想要结果 Id ProductName MainCategory AdditionalCategory尺寸 1美国烤咖啡10 5美国烤咖啡夏威夷10 9美国烤咖啡Kona 10 如有可能请给我代码 谢谢Advance 解决方案 如果你想要大小,然后你应该在查询中包括列:) 由于你似乎只想要最小的大小值,那么你必须使用MIN()函数。 SELECT Productname,Maincategory,AdditionalCategory,MIN(Size) FROM testproducts GROUP BY Productname,Maincategory,AdditionalCategory 希望这有帮助。 试试这个: DECLARE @ tmp AS TABLE (Id INT IDENTITY ( 1 , 1 ),ProductName VARCHAR ( 30 ),MainCategory VARCHAR ( 30 ),AdditionalCategory VARCHAR ( 30 ),大小 INT ) INSERT INTO @ tmp (ProductName,MainCategory,AdditionalCategory,size) VALUES (' American Roast',' 咖啡', NULL , 10 ),( ' American Roast',' Coffee', NULL , 12 ),(' American Roast',' Coffee', NULL , 14 ) ,(' American Roast',' Coffee', NULL , 16 ), (' American Roast',' Coffee',' Hawaiian', 10 ),(' American Roast',' 咖啡',' Hawaiian', 12 ),(' American Roast',' Coffee',' Hawaiian', 14 ),(' American Roast',' Coffee',' Hawaiian', 16 ) ,(' American Roast',' Coffee',' Kona', 10 ),(' American Roast',' Coffee', ' Kona', 12 ),(' American Roast',' Coffee',' Kona', 14 ),(' American Roast',' Coffee', ' Kona', 16 ) SELECT t2.Id,t1.ProductName,t1.MainCategory,t1.AdditionalCategory,t1.size FROM ( SELECT ProductName,MainCategory,AdditionalCategory,MIN(size) AS 大小 FROM @ tmp GROUP BY ProductName,MainCategory,AdditionalCat egory ) AS t1 LEFT JOIN @ tmp AS t2 ON t1 .ProductName = t2.ProductName AND t1.MainCategory = t2.MainCategory AND COALESCE (t1.AdditionalCategory,' - ')= COALESCE (t2.AdditionalCategory,' - ') AND t1.size = t2.size 结果: 1美国烤咖啡NULL 10 5美国烤咖啡夏威夷10 9美国烤咖啡Kona 10 您不能将 Id 与 MIN()一起添加函数,因为它强制将 Id 添加到 GROUP BY 列表。实现预期输出的唯一方法是使用子查询。 为sol1添加了ID。 选择Min(id), ProductName,MainCategory,AdditionalCategory,MIN(size) 来自testproducts 按产品名称分类,MainCategory,AdditionalCategory Hi,I have table like thisId ProductNameMainCategory AdditionalCategorysize 1 American RoastCoffee 102 American RoastCoffee 123 American RoastCoffee 144 American RoastCoffee 165 American RoastCoffee Hawaiian 106 American RoastCoffee Hawaiian 127 American RoastCoffee Hawaiian 148 American RoastCoffee Hawaiian 169 American RoastCoffee Kona 1010 American RoastCoffee Kona 1211 American RoastCoffee Kona 1412 American RoastCoffee Kona 16I have use group by class in this table select Productname,Maincategory,AdditionalCategory1 from testproductsgroup by Productname,Maincategory,AdditionalCategory1 I got Result like this ProductNameMainCategory AdditionalCategoryAmerican Roast Coffee American Roast Coffee HawaiianAmerican Roast Coffee KonaBut I want Result Id ProductName MainCategory AdditionalCategory Size 1 American Roast Coffee 10 5 American Roast Coffee Hawaiian 10 9 American Roast Coffee Kona 10If any possible please give me codeThanks Advance 解决方案 If you want the size, then you should include the column in your query :)And since you seem to only want the minimum size value, then you have to use the MIN() function.SELECT Productname, Maincategory, AdditionalCategory, MIN(Size) FROM testproductsGROUP BY Productname, Maincategory, AdditionalCategoryHope this helps.Try this:DECLARE @tmp AS TABLE (Id INT IDENTITY(1,1), ProductName VARCHAR(30), MainCategory VARCHAR(30), AdditionalCategory VARCHAR(30), size INT)INSERT INTO @tmp (ProductName, MainCategory, AdditionalCategory, size)VALUES('American Roast', 'Coffee', NULL, 10),('American Roast', 'Coffee', NULL, 12),('American Roast', 'Coffee', NULL, 14),('American Roast', 'Coffee', NULL, 16),('American Roast', 'Coffee', 'Hawaiian', 10),('American Roast', 'Coffee', 'Hawaiian', 12),('American Roast', 'Coffee', 'Hawaiian', 14),('American Roast', 'Coffee', 'Hawaiian', 16),('American Roast', 'Coffee', 'Kona', 10),('American Roast', 'Coffee', 'Kona', 12),('American Roast', 'Coffee', 'Kona', 14),('American Roast', 'Coffee', 'Kona', 16)SELECT t2.Id, t1.ProductName, t1.MainCategory, t1.AdditionalCategory, t1.sizeFROM ( SELECT ProductName, MainCategory, AdditionalCategory, MIN(size) AS size FROM @tmp GROUP BY ProductName, MainCategory, AdditionalCategory) AS t1 LEFT JOIN @tmp AS t2 ON t1.ProductName = t2.ProductName AND t1.MainCategory = t2.MainCategory AND COALESCE(t1.AdditionalCategory, '-') = COALESCE(t2.AdditionalCategory,'-') AND t1.size = t2.sizeResult:1American RoastCoffeeNULL105American RoastCoffeeHawaiian109American RoastCoffeeKona10You can't add Id together with MIN() function, because it enforces to add Id to GROUP BY list. The only way to achieve expected output is to use subquery.Added Id to sol1 .Select Min(id), ProductName,MainCategory,AdditionalCategory,MIN(size)from testproductsGroup by ProductName,MainCategory,AdditionalCategory 这篇关于如何在sql中使用GroupBy?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持! 09-16 01:04